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csh




SYNOPSIS

       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l


DESCRIPTION

       tcsh is an enhanced but completely compatible  version  of
       the  Berkeley  UNIX C shell, csh(1).  It is a command lan­
       guage interpreter usable  both  as  an  interactive  login
       shell and a shell script command processor.  It includes a
       command-line editor (see The  command-line  editor),  pro­
       grammable  word  completion  (see Completion and listing),
       spelling correction (see Spelling correction),  a  history
       mechanism  (see  History  substitution),  job control (see
       Jobs) and a  C-like  syntax.   The  NEW  FEATURES  section
       describes   major   enhancements   of  tcsh  over  csh(1).
       Throughout this manual, features of tcsh not found in most
       csh(1)  implementations (specifically, the 4.4BSD csh) are
       labeled with `(+)', and  features  which  are  present  in
       csh(1)  but not usually documented are labeled with `(u)'.

   Argument list processing
       If the first argument (argument 0) to  the  shell  is  `-'
       then it is a login shell.  A login shell can be also spec­
       ified by invoking the shell with the -l flag as  the  only
       argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from option processing, causing any
           further  shell  arguments  to be treated as non-option
           arguments.  The remaining arguments will not be inter­
           preted  as  shell  options.   This may be used to pass
           options to a shell script without confusion or  possi­
           ble  subterfuge.  The shell will not run a set-user ID
           script without this option.

       -c  Commands are read from the following  argument  (which
           must  be  present,  and  must  be  a single argument),
           stored in the command shell  variable  for  reference,
           and  executed.   Any remaining arguments are placed in
           the argv shell variable.

       -d  The shell loads the directory stack from ~/.cshdirs as
           described  under  Startup and shutdown, whether or not
           it is a login shell. (+)

       -Dname[=value]
           Sets  the  environment   variable   name   to   value.
           (Domain/OS only) (+)

       -e  The  shell  exits  if  any  invoked command terminates

       -m  The  shell  loads ~/.tcshrc even if it does not belong
           to the effective user.  Newer versions  of  su(1)  can
           pass -m to the shell. (+)

       -n  The  shell  parses commands but does not execute them.
           This aids in debugging shell scripts.

       -q  The shell accepts SIGQUIT (see  Signal  handling)  and
           behaves when it is used under a debugger.  Job control
           is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line  of  input.
           A  `\' may be used to escape the newline at the end of
           this line and continue onto another line.

       -v  Sets the verbose shell variable, so that command input
           is echoed after history substitution.

       -x  Sets  the  echo  shell  variable, so that commands are
           echoed immediately before execution.

       -V  Sets the verbose shell variable even before  executing
           ~/.tcshrc.

       -X  Is to -x as -V is to -v.

       After  processing  of  flag arguments, if arguments remain
       but none of the -c, -i, -s, or -t options were given,  the
       first argument is taken as the name of a file of commands,
       or ``script'', to be executed.  The shell opens this  file
       and  saves  its  name for possible resubstitution by `$0'.
       Because many systems use either the standard version 6  or
       version  7  shells  whose shell scripts are not compatible
       with this shell, the shell uses such a `standard' shell to
       execute a script whose first character is not a `#', i.e.,
       that does not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A login shell begins by executing commands from the system
       files /etc/csh.cshrc and /etc/csh.login.  It then executes
       commands  from  files  in the user's home directory: first
       ~/.tcshrc (+) or, if ~/.tcshrc  is  not  found,  ~/.cshrc,
       then  ~/.history (or the value of the histfile shell vari­
       able), then ~/.login, and finally ~/.cshdirs (or the value
       of  the  dirsfile shell variable) (+).  The shell may read
       /etc/csh.login before instead of after /etc/csh.cshrc, and
       ~/.login before instead of after ~/.tcshrc or ~/.cshrc and
       specific commands, or can  have  both  a  ~/.cshrc  and  a
       ~/.tcshrc   which   sources   (see  the  builtin  command)
       ~/.cshrc.  The rest of this  manual  uses  `~/.tcshrc'  to
       mean  `~/.tcshrc or, if ~/.tcshrc is not found, ~/.cshrc'.

       In the normal case, the shell begins reading commands from
       the  terminal,  prompting with `> '.  (Processing of argu­
       ments and the use of the shell to process files containing
       command  scripts  are described later.)  The shell repeat­
       edly reads a line of command input, breaks it into  words,
       places  it on the command history list, parses it and exe­
       cutes each command in the line.

       One can log out by typing `^D' on an empty line,  `logout'
       or  `login'  or  via the shell's autologout mechanism (see
       the autologout shell variable).  When a login shell termi­
       nates  it  sets  the  logout shell variable to `normal' or
       `automatic' as appropriate, then  executes  commands  from
       the  files  /etc/csh.logout  and ~/.logout.  The shell may
       drop DTR on logout if so compiled; see the  version  shell
       variable.

       The  names  of the system login and logout files vary from
       system to system for compatibility with  different  csh(1)
       variants; see FILES.

   Editing
       We first describe The command-line editor.  The Completion
       and listing and Spelling correction sections describe  two
       sets  of functionality that are implemented as editor com­
       mands but which deserve  their  own  treatment.   Finally,
       Editor  commands  lists  and describes the editor commands
       specific to the shell and their default bindings.

   The command-line editor (+)
       Command-line input can be edited using key sequences  much
       like  those  used  in  GNU  Emacs or vi(1).  The editor is
       active only when the edit shell variable is set, which  it
       is  by default in interactive shells.  The bindkey builtin
       can display and  change  key  bindings.   Emacs-style  key
       bindings  are  used  by default (unless the shell was com­
       piled otherwise; see  the  version  shell  variable),  but
       bindkey  can  change the key bindings to vi-style bindings
       en masse.

       The shell always binds the arrow keys (as defined  in  the
       TERMCAP environment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       with any non-alphanumeric  characters  not  in  the  shell
       variable   wordchars,  while  the  shell  recognizes  only
       whitespace and some of the characters with  special  mean­
       ings to it, listed under Lexical structure.

   Completion and listing (+)
       The  shell  is  often  able to complete words when given a
       unique abbreviation.  Type part of a word (for example `ls
       /usr/lost')  and  hit the tab key to run the complete-word
       editor  command.   The  shell   completes   the   filename
       `/usr/lost'  to  `/usr/lost+found/',  replacing the incom­
       plete word with the complete word  in  the  input  buffer.
       (Note  the  terminal `/'; completion adds a `/' to the end
       of completed directories and a space to the end  of  other
       completed  words,  to  speed  typing  and provide a visual
       indicator of successful completion.  The  addsuffix  shell
       variable  can  be  unset to prevent this.)  If no match is
       found (perhaps `/usr/lost+found' doesn't exist), the  ter­
       minal  bell  rings.  If the word is already complete (per­
       haps there is a `/usr/lost' on your system, or perhaps you
       were  thinking  too far ahead and typed the whole thing) a
       `/' or space is added to  the  end  if  it  isn't  already
       there.

       Completion  works  anywhere  in  the line, not at just the
       end; completed text pushes the rest of  the  line  to  the
       right.   Completion  in the middle of a word often results
       in leftover characters to the right  of  the  cursor  that
       need to be deleted.

       Commands  and  variables can be completed in much the same
       way.  For example, typing `em[tab]' would complete `em' to
       `emacs'  if  emacs  were  the  only command on your system
       beginning with `em'.  Completion can find a command in any
       directory  in  path  or  if given a full pathname.  Typing
       `echo $ar[tab]' would complete  `$ar'  to  `$argv'  if  no
       other variable began with `ar'.

       The shell parses the input buffer to determine whether the
       word you want to complete should be completed as  a  file­
       name,  command  or variable.  The first word in the buffer
       and the first word following `;', `|', `|&', `&&' or  `||'
       is  considered to be a command.  A word beginning with `$'
       is considered to be a variable.  Anything else is a  file­
       name.  An empty line is `completed' as a filename.

       You  can  list  the  possible completions of a word at any
       time by typing `^D' to run the  delete-char-or-list-or-eof
       editor  command.  The shell lists the possible completions
       using the ls-F builtin (q.v.)  and reprints the prompt and
       unfinished command line, for example:

       word being completed.

       A filename to be completed can contain variables, your own
       or  others'  home  directories  abbreviated  with `~' (see
       Filename substitution) and directory stack entries  abbre­
       viated  with  `=' (see Directory stack substitution).  For
       example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/

       or

           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note that variables can also be expanded  explicitly  with
       the expand-variables editor command.

       delete-char-or-list-or-eof  lists  at  only the end of the
       line; in the middle of a line  it  deletes  the  character
       under  the cursor and on an empty line it logs one out or,
       if ignoreeof is set, does nothing.  `M-^D', bound  to  the
       editor  command  list-choices, lists completion possibili­
       ties anywhere on a line, and list-choices (or any  one  of
       the  related editor commands that do or don't delete, list
       and/or log out, listed  under  delete-char-or-list-or-eof)
       can  be  bound to `^D' with the bindkey builtin command if
       so desired.

       The complete-word-fwd and complete-word-back  editor  com­
       mands  (not  bound  to any keys by default) can be used to
       cycle up and down through the  list  of  possible  comple­
       tions,  replacing the current word with the next or previ­
       ous word in the list.

       The shell variable fignore can be set to a  list  of  suf­
       fixes  to  be ignored by completion.  Consider the follow­
       ing:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o

       the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and  typed  `mail -f c.l.c[tab]', it would be completed to
       `mail -f comp.lang.c', and ^D would list `comp.lang.c' and
       `comp.lang.c++'.    `mail   -f   c..c++[^D]'   would  list
       `comp.lang.c++'   and    `comp.std.c++'.     Typing    `rm
       a--file[^D]' in the following directory

           A_silly_file                         a-hyphenated-file
           another_silly_file

       would list all three files, because case  is  ignored  and
       hyphens and underscores are equivalent.  Periods, however,
       are not equivalent to hyphens or underscores.

       Completion and listing are affected by several other shell
       variables: recexact can be set to complete on the shortest
       possible unique match, even if more typing might result in
       a longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just  beeps,  because `fo' could expand to `fod' or `foo',
       but if we type another `o',

           > rm foo[tab]
           > rm foo

       the completion completes on `foo', even though `food'  and
       `foonly'  also  match.   autoexpand  can be set to run the
       expand-history  editor  command  before  each   completion
       attempt,  autocorrect  can  be set to spelling-correct the
       word to be completed (see Spelling correction) before each
       completion attempt and correct can be set to complete com­
       mands automatically after one  hits  `return'.   matchbeep
       can  be set to make completion beep or not beep in a vari­
       ety of situations, and nobeep can be set to never beep  at
       all.   nostat  can  be set to a list of directories and/or
       patterns that match directories to prevent the  completion
       mechanism  from stat(2)ing those directories.  listmax and
       listmaxrows can be set to limit the number  of  items  and
       rows  (respectively) that are listed without asking first.
       recognize_only_executables can be set to  make  the  shell
       list  only  executables  when  listing commands, but it is
       quite slow.

       entire  input  buffer  with  spell-line  (usually bound to
       M-$).  The correct shell variable can be set to  `cmd'  to
       correct  the  command  name or `all' to correct the entire
       line each time return is typed, and autocorrect can be set
       to correct the word to be completed before each completion
       attempt.

       When spelling correction is invoked in any of  these  ways
       and  the shell thinks that any part of the command line is
       misspelled, it prompts with the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One can answer `y' or space to execute the corrected line,
       `e'  to leave the uncorrected command in the input buffer,
       `a' to abort the command as if `^C' had been hit, and any­
       thing else to execute the original line unchanged.

       Spelling  correction  recognizes  user-defined completions
       (see the complete builtin command).  If an input word in a
       position  for  which  a  completion is defined resembles a
       word in the completion list, spelling correction registers
       a  misspelling  and  suggests the latter word as a correc­
       tion.  However, if the input word does not  match  any  of
       the  possible completions for that position, spelling cor­
       rection does not register a misspelling.

       Like completion, spelling correction works anywhere in the
       line, pushing the rest of the line to the right and possi­
       bly leaving extra characters to the right of the cursor.

       Beware: spelling correction is not guaranteed to work  the
       way one intends, and is provided mostly as an experimental
       feature.  Suggestions and improvements are welcome.

   Editor commands (+)
       `bindkey' lists key bindings and `bindkey  -l'  lists  and
       briefly describes editor commands.  Only new or especially
       interesting  editor  commands  are  described  here.   See
       emacs(1)  and  vi(1) for descriptions of each editor's key
       bindings.

       The character or characters to which each command is bound
       by  default is given in parentheses.  `^character' means a
       control character  and  `M-character'  a  meta  character,
       typed as escape-character on terminals without a meta key.
       Case counts, but commands that are  bound  to  letters  by
       default are bound to both lower- and uppercase letters for
       convenience.

       complete-word-raw (^X-tab)
               Like  complete-word, but ignores user-defined com­
               pletions.

       copy-prev-word (M-^_)
               Copies the previous word in the current line  into
               the input buffer.  See also insert-last-word.

       dabbrev-expand (M-/)
               Expands  the  current word to the most recent pre­
               ceding one for which the current is a leading sub­
               string, wrapping around the history list (once) if
               necessary.  Repeating dabbrev-expand  without  any
               intervening  typing  changes  to the next previous
               word etc., skipping identical  matches  much  like
               history-search-backward does.

       delete-char   (bound   to  `Del'  if  using  the  standard
       /etc/csh.cshrc)
               Deletes  the character under the cursor.  See also
               delete-char-or-list-or-eof.

       delete-char-or-eof (not bound)
               Does delete-char if there is a character under the
               cursor  or end-of-file on an empty line.  See also
               delete-char-or-list-or-eof.

       delete-char-or-list (not bound)
               Does delete-char if there is a character under the
               cursor  or  list-choices  at  the end of the line.
               See also delete-char-or-list-or-eof.

       delete-char-or-list-or-eof (^D)
               Does delete-char if there is a character under the
               cursor,  list-choices  at  the  end of the line or
               end-of-file on an  empty  line.   See  also  those
               three  commands,  each of which does only a single
               action,  and  delete-char-or-eof,  delete-char-or-
               list and list-or-eof, each of which does a differ­
               ent two out of the three.

       down-history (down-arrow, ^N)
               Like up-history, but steps down, stopping  at  the
               original input line.

       end-of-file (not bound)
               Signals  an end of file, causing the shell to exit
               unless the ignoreeof shell variable (q.v.) is  set
               to prevent this.  See also delete-char-or-list-or-
               eof.

       expand-history (M-space)
               Expands  the  variable  to the left of the cursor.
               See Variable substitution.

       history-search-backward (M-p, M-P)
               Searches backwards through the history list for  a
               command beginning with the current contents of the
               input buffer up to the cursor and copies  it  into
               the  input  buffer.   The  search  string may be a
               glob-pattern (see Filename substitution)  contain­
               ing  `*', `?', `[]' or `{}'.  up-history and down-
               history will proceed from the appropriate point in
               the history list.  Emacs mode only.  See also his­
               tory-search-forward and i-search-back.

       history-search-forward (M-n, M-N)
               Like history-search-backward,  but  searches  for­
               ward.

       i-search-back (not bound)
               Searches  backward  like  history-search-backward,
               copies the first match into the input buffer  with
               the  cursor  positioned at the end of the pattern,
               and prompts with `bck:  '  and  the  first  match.
               Additional  characters  may be typed to extend the
               search, i-search-back may  be  typed  to  continue
               searching  with  the same pattern, wrapping around
               the history list if necessary, (i-search-back must
               be  bound  to a single character for this to work)
               or one of the following special characters may  be
               typed:

                   ^W      Appends the rest of the word under the
                           cursor to the search pattern.
                   delete (or any character  bound  to  backward-
                   delete-char)
                           Undoes the effect of the last  charac­
                           ter typed and deletes a character from
                           the search pattern if appropriate.
                   ^G      If the previous search was successful,
                           aborts  the  entire  search.   If not,
                           goes  back  to  the  last   successful
                           search.
                   escape  Ends  the  search, leaving the current
                           line in the input buffer.

               Any other character not bound to  self-insert-com­
               mand  terminates  the  search, leaving the current
               line in the input buffer, and is then  interpreted
               as normal input.  In particular, a carriage return
               causes the current line  to  be  executed.   Emacs
               mode  only.   See  also  i-search-fwd and history-
               search-backward.

       list-choices-raw (^X-^D)
               Like list-choices, but ignores  user-defined  com­
               pletions.

       list-glob (^X-g, ^X-G)
               Lists  (via the ls-F builtin) matches to the glob-
               pattern (see Filename substitution) to the left of
               the cursor.

       list-or-eof (not bound)
               Does list-choices or end-of-file on an empty line.
               See also delete-char-or-list-or-eof.

       magic-space (not bound)
               Expands history substitutions in the current line,
               like  expand-history, and appends a space.  magic-
               space is designed to be bound to  the  space  bar,
               but is not bound by default.

       normalize-command (^X-?)
               Searches  for  the current word in PATH and, if it
               is found, replaces it with the full  path  to  the
               executable.    Special   characters   are  quoted.
               Aliases  are  expanded  and  quoted  but  commands
               within  aliases  are  not.  This command is useful
               with commands that  take  commands  as  arguments,
               e.g., `dbx' and `sh -x'.

       normalize-path (^X-n, ^X-N)
               Expands  the  current  word as described under the
               `expand' setting of the symlinks shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current  input  line  and  looks  for  a
               stopped  job  with a name equal to the last compo­
               nent of the file name part of the EDITOR or VISUAL
               environment variables, or, if neither is set, `ed'
               or `vi'.  If such a job is found, it is  restarted
               as  if  `fg %job' had been typed.  This is used to
               toggle back and forth between an  editor  and  the
               shell  easily.   Some  people bind this command to
               `^Z' so they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the current command,
               using  the same notion of `current command' as the
               completion routines, and prints it.  There  is  no
               way to use a pager; run-help is designed for short
               help files.  If the special alias  helpcommand  is
               lines, but the inputmode shell variable can be set
               to  `insert'  or  `overwrite' to put the editor in
               that mode at the beginning of each line.  See also
               overwrite-mode.

       sequence-lead-in (arrow prefix, meta prefix, ^X)
               Indicates  that  the following characters are part
               of a multi-key sequence.  Binding a command  to  a
               multi-key  sequence  really  creates two bindings:
               the first character to  sequence-lead-in  and  the
               whole  sequence  to  the  command.   All sequences
               beginning with a character bound to sequence-lead-
               in  are  effectively bound to undefined-key unless
               bound to another command.

       spell-line (M-$)
               Attempts to correct the spelling of each  word  in
               the  input  buffer,  like  spell-word, but ignores
               words whose first character is one  of  `-',  `!',
               `^'  or  `%', or which contain `\', `*' or `?', to
               avoid problems with  switches,  substitutions  and
               the like.  See Spelling correction.

       spell-word (M-s, M-S)
               Attempts  to  correct  the spelling of the current
               word  as  described  under  Spelling   correction.
               Checks  each  component of a word which appears to
               be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands or `unexpands'  history  substitutions  in
               the input buffer.  See also expand-history and the
               autoexpand shell variable.

       undefined-key (any unbound key)
               Beeps.

       up-history (up-arrow, ^P)
               Copies the previous entry in the history list into
               the  input  buffer.   If  histlit is set, uses the
               literal form of the entry.   May  be  repeated  to
               step  up through the history list, stopping at the
               top.

       vi-search-back (?)
               Prompts with `?' for a search string (which may be
               a  glob-pattern, as with history-search-backward),
               searches for it  and  copies  it  into  the  input
               buffer.   The  bell  rings  if  no match is found.
               Hitting return ends the search and leaves the last
               match  in  the  input buffer.  Hitting escape ends
               the search and executes the match.  vi mode  only.

       When the shell's input is not a  terminal,  the  character
       `#' is taken to begin a comment.  Each `#' and the rest of
       the input line on which it  appears  is  discarded  before
       further parsing.

       A special character (including a blank or tab) may be pre­
       vented from having its special meaning, and possibly  made
       part  of  another  word,  by preceding it with a backslash
       (`\') or enclosing it in single  (`''),  double  (`"')  or
       backward  (``')  quotes.  When not otherwise quoted a new­
       line preceded by a `\'  is  equivalent  to  a  blank,  but
       inside quotes this sequence results in a newline.

       Furthermore,  all Substitutions (see below) except History
       substitution can be prevented by enclosing the strings (or
       parts  of strings) in which they appear with single quotes
       or by quoting the crucial character(s) (e.g., `$'  or  ``'
       for  Variable substitution or Command substitution respec­
       tively) with `\'.  (Alias substitution  is  no  exception:
       quoting  in  any  way any character of a word for which an
       alias has been defined prevents substitution of the alias.
       The  usual way of quoting an alias is to precede it with a
       backslash.) History substitution  is  prevented  by  back­
       slashes  but  not  by  single quotes.  Strings quoted with
       double or backward quotes  undergo  Variable  substitution
       and Command substitution, but other substitutions are pre­
       vented.

       Text inside single or double quotes becomes a single  word
       (or  part  of  one).   Metacharacters  in  these  strings,
       including blanks and tabs, do  not  form  separate  words.
       Only  in one special case (see Command substitution below)
       can a double-quoted string yield parts of  more  than  one
       word; single-quoted strings never do.  Backward quotes are
       special: they signal Command  substitution  (q.v.),  which
       may result in more than one word.

       Quoting  complex strings, particularly strings which them­
       selves  contain  quoting  characters,  can  be  confusing.
       Remember that quotes need not be used as they are in human
       writing!  It may be easier to quote not an entire  string,
       but  only  those  parts  of the string which need quoting,
       using different types of quoting to do so if  appropriate.

       The  backslash_quote  shell  variable (q.v.) can be set to
       make backslashes always quote `\', `'', and `"'.  (+) This
       may  make  complex  quoting tasks easier, but it can cause
       syntax errors in csh(1) scripts.

   Substitutions
       We now describe the various transformations the shell per­
       Saved  commands  are  numbered  sequentially  from  1  and
       stamped with the time.  It is not usually necessary to use
       event numbers, but the current event number  can  be  made
       part  of  the prompt by placing an `!' in the prompt shell
       variable.

       The shell actually saves history in expanded  and  literal
       (unexpanded) forms.  If the histlit shell variable is set,
       commands that display and store history  use  the  literal
       form.

       The  history  builtin  command can print, store in a file,
       restore and clear the history list at any  time,  and  the
       savehist and histfile shell variables can be can be set to
       store the history list automatically on logout and restore
       it on login.

       History  substitutions  introduce  words  from the history
       list into the input stream, making it easy to repeat  com­
       mands,  repeat arguments of a previous command in the cur­
       rent command, or fix spelling  mistakes  in  the  previous
       command  with  little  typing  and a high degree of confi­
       dence.

       History substitutions begin with the character `!'.   They
       may  begin  anywhere  in the input stream, but they do not
       nest.  The `!' may be preceded by a  `\'  to  prevent  its
       special   meaning;   for  convenience,  a  `!'  is  passed
       unchanged when it is followed by a  blank,  tab,  newline,
       `='  or  `('.   History  substitutions  also occur when an
       input line begins with  `^'.   This  special  abbreviation
       will  be  described  later.  The characters used to signal
       history substitution (`!' and `^') can be changed by  set­
       ting  the  histchars shell variable.  Any input line which
       contains a history substitution is printed  before  it  is
       executed.

       A  history  substitution  may  have  an ``event specifica­
       tion'', which indicates the event from which words are  to
       be  taken, a ``word designator'', which selects particular
       words from the chosen event, and/or a ``modifier'',  which
       manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An offset, referring to the event n before the
                   current event
           #       The current event.  This should be used  care­
                   fully  in  csh(1), where there is no check for
                   recursion.  tcsh allows 10  levels  of  recur­
                   sion.  (+)

       The commands are shown with their event numbers  and  time
       stamps.  The current event, which we haven't typed in yet,
       is event 13.  `!11' and `!-2' refer  to  event  11.   `!!'
       refers to the previous event, 12.  `!!' can be abbreviated
       `!' if it is followed by `:'  (`:'  is  described  below).
       `!n'  refers  to event 9, which begins with `n'.  `!?old?'
       also refers to event 12, which  contains  `old'.   Without
       word  designators  or  modifiers history references simply
       expand to the entire event, so we might type `!cp' to redo
       the  copy  command  or  `!!|more'  if  the  `diff'  output
       scrolled off the top of the screen.

       History references may be insulated from  the  surrounding
       text with braces if necessary.  For example, `!vdoc' would
       look for a command beginning with  `vdoc',  and,  in  this
       example,  not  find  one, but `!{v}doc' would expand unam­
       biguously to `vi wumpus.mandoc'.  Even in braces,  history
       substitutions do not nest.

       (+)  While  csh(1)  expands, for example, `!3d' to event 3
       with the letter `d' appended to it, tcsh expands it to the
       last  event  beginning  with `3d'; only completely numeric
       arguments are treated as event  numbers.   This  makes  it
       possible  to  recall  events  beginning  with numbers.  To
       expand `!3d' as in csh(1) say `!\3d'.

       To select words from an event  we  can  follow  the  event
       specification  by  a  `:' and a designator for the desired
       words.  The words of an input line are  numbered  from  0,
       the  first (usually command) word being 0, the second word
       (first argument) being 1, etc.  The basic word designators
       are:

           0       The first (command) word
           n       The nth argument
           ^       The first argument, equivalent to `1'
           $       The last argument
           %       The word matched by an ?s? search
           x-y     A range of words
           -y      Equivalent to `0-y'
           *       Equivalent  to  `^-$',  but returns nothing if
                   the event contains only 1 word
           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word
                   (`$')

       Selected  words  are  inserted into the command line sepa­
       rated by single blanks.  For example, the  `diff'  command
       in  the  previous  example  might have been typed as `diff
       !!:1.old !!:1' (using `:1' to select  the  first  argument
       from  the  previous event) or `diff !-2:2 !-2:1' to select
       and swap the arguments  from  the  `cp'  command.   If  we

       A history reference may have  a  word  designator  but  no
       event specification.  It then references the previous com­
       mand.  Continuing our `diff' example, we could  have  said
       simply  `diff  !^.old  !^' or, to get the arguments in the
       opposite order, just `diff !*'.

       The word or words in a history reference can be edited, or
       ``modified'',  by following it with one or more modifiers,
       each preceded by a `:':

           h       Remove a trailing pathname component,  leaving
                   the head.
           t       Remove  all leading pathname components, leav­
                   ing the tail.
           r       Remove a filename  extension  `.xxx',  leaving
                   the root name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute l for r.  l is simply a string like
                   r, not a regular expression as in  the  epony­
                   mous ed(1) command.  Any character may be used
                   as the delimiter in place of `/'; a `\' can be
                   used  to  quote  the delimiter inside l and r.
                   The character `&' in the r is replaced  by  l;
                   `\'  also  quotes  `&'.  If l is empty (``''),
                   the l from a previous substitution  or  the  s
                   from  a  previous `?s?' event specification is
                   used.  The trailing delimiter may  be  omitted
                   if it is immediately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply  the  following  modifier  once  to each
                   word.
           a (+)   Apply the following modifier as many times  as
                   possible to a single word.  `a' and `g' can be
                   used together to apply  a  modifier  globally.
                   In  the  current implementation, using the `a'
                   and `s' modifiers  together  can  lead  to  an
                   infinite  loop.  For example, `:as/f/ff/' will
                   never terminate.  This behavior  might  change
                   in the future.
           p       Print  the new command line but do not execute
                   it.
           q       Quote the substituted words,  preventing  fur­
                   ther substitutions.
           x       Like  q,  but break into words at blanks, tabs
                   and newlines.

       Modifiers are applied to only the  first  modifiable  word
       (unless  `g'  is  used).  It is an error for no word to be
       modifiable.
       make  the  spelling  correction  in  the previous example.
       This is the  only  history  substitution  which  does  not
       explicitly begin with `!'.

       (+)  In  csh  as such, only one modifier may be applied to
       each history or variable expansion.  In  tcsh,  more  than
       one may be used, for example

           % mv wumpus.man /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In  csh, the result would be `wumpus.1:r'.  A substitution
       followed by a colon may need to be insulated from it  with
       braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The  first attempt would succeed in csh but fails in tcsh,
       because tcsh expects another  modifier  after  the  second
       colon rather than `$'.

       Finally,  history  can  be  accessed through the editor as
       well as through the substitutions just described.  The up-
       and down-history, history-search-backward and -forward, i-
       search-back and -fwd, vi-search-back and -fwd,  copy-prev-
       word  and  insert-last-word  editor  commands  search  for
       events in the history list and copy them  into  the  input
       buffer.    The   toggle-literal-history   editor   command
       switches between the expanded and literal forms of history
       lines in the input buffer.  expand-history and expand-line
       expand history substitutions in the current  word  and  in
       the entire input buffer respectively.

   Alias substitution
       The  shell  maintains  a list of aliases which can be set,
       unset and printed  by  the  alias  and  unalias  commands.
       After  a  command line is parsed into simple commands (see
       Commands) the first word of each  command,  left-to-right,
       is  checked  to  see if it has an alias.  If so, the first
       word is replaced by the alias.  If the  alias  contains  a
       history   reference,  it  undergoes  History  substitution
       (q.v.) as though the original command  were  the  previous
       input  line.  If the alias does not contain a history ref­
       erence, the argument list is left untouched.

       Thus if the alias for `ls' were `ls -l'  the  command  `ls
       /usr'  would  become  `ls -l /usr', the argument list here
       aliases.

   Variable substitution
       The shell maintains a list of variables, each of which has
       as  value  a  list  of  zero or more words.  The values of
       shell variables can be displayed and changed with the  set
       and  unset commands.  The system maintains its own list of
       ``environment'' variables.  These  can  be  displayed  and
       changed with printenv, setenv and unsetenv.

       (+)  Variables  may be made read-only with `set -r' (q.v.)
       Read-only variables may not be modified or unset; attempt­
       ing  to do so will cause an error.  Once made read-only, a
       variable cannot be made writable, so `set  -r'  should  be
       used  with  caution.  Environment variables cannot be made
       read-only.

       Some variables are set by the shell or referred to by  it.
       For instance, the argv variable is an image of the shell's
       argument list, and words  of  this  variable's  value  are
       referred  to  in  special  ways.   Some  of  the variables
       referred to by the shell are toggles; the shell  does  not
       care  what  their  value  is, only whether they are set or
       not.  For instance, the verbose variable is a toggle which
       causes  command  input  to be echoed.  The -v command line
       option sets this variable.  Special shell variables  lists
       all variables which are referred to by the shell.

       Other  operations  treat  variables  numerically.  The `@'
       command permits numeric calculations to be  performed  and
       the  result  assigned to a variable.  Variable values are,
       however, always represented as  (zero  or  more)  strings.
       For the purposes of numeric operations, the null string is
       considered to be zero, and the second and subsequent words
       of multi-word values are ignored.

       After  the  input  line  is aliased and parsed, and before
       each command is executed, variable  substitution  is  per­
       formed  keyed  by  `$'  characters.  This expansion can be
       prevented by preceding the `$' with a  `\'  except  within
       `"'s  where  it  always  occurs,  and within `''s where it
       never occurs.  Strings quoted by ``' are interpreted later
       (see  Command substitution below) so `$' substitution does
       not occur there until later, if at all.  A `$'  is  passed
       unchanged if followed by a blank, tab, or end-of-line.

       Input/output  redirections  are recognized before variable
       expansion, and are variable expanded  separately.   Other­
       wise,  the  command  name  and  entire  argument  list are
       expanded together.  It is  thus  possible  for  the  first
       (command)  word  (to this point) to generate more than one
       word, the first of which becomes the command name, and the
       is an error to reference a variable which is not set.

       $name
       ${name} Substitutes  the  words  of  the value of variable
               name, each separated by a blank.  Braces  insulate
               name  from following characters which would other­
               wise be part of it.  Shell  variables  have  names
               consisting of up to 20 letters and digits starting
               with a letter.  The underscore character  is  con­
               sidered  a  letter.   If name is not a shell vari­
               able, but is set in  the  environment,  then  that
               value is returned (but `:' modifiers and the other
               forms given below are not available in this case).
       $name[selector]
       ${name[selector]}
               Substitutes only the selected words from the value
               of name.  The selector is subjected to `$' substi­
               tution  and  may consist of a single number or two
               numbers separated by a `-'.  The first word  of  a
               variable's  value  is  numbered `1'.  If the first
               number of a range is omitted it defaults  to  `1'.
               If  the  last  member  of  a  range  is omitted it
               defaults to `$#name'.  The  selector  `*'  selects
               all  words.   It is not an error for a range to be
               empty if the second  argument  is  omitted  or  in
               range.
       $0      Substitutes  the  name of the file from which com­
               mand input is being read.  An error occurs if  the
               name is not known.
       $number
       ${number}
               Equivalent to `$argv[number]'.
       $*      Equivalent  to  `$argv',  which  is  equivalent to
               `$argv[*]'.

       The `:' modifiers described  under  History  substitution,
       except  for  `:p',  can  be  applied  to the substitutions
       above.  More than one may be  used.   (+)  Braces  may  be
       needed  to insulate a variable substitution from a literal
       colon just as with History substitution (q.v.); any  modi­
       fiers must appear within the braces.

       The  following  substitutions can not be modified with `:'
       modifiers.

       $?name
       ${?name}
               Substitutes the string `1' if name is set, `0'  if
               it is not.
       $?0     Substitutes  `1'  if the current input filename is
               known, `0' if it is not.  Always `0'  in  interac­
               tive shells.

       $!      Substitutes the (decimal) process  number  of  the
               last  background  process  started  by this shell.
               (+)
       $_      Substitutes the command line of the  last  command
               executed.  (+)
       $<      Substitutes  a  line from the standard input, with
               no further interpretation thereafter.  It  can  be
               used  to read from the keyboard in a shell script.
               (+) While csh always quotes  $<,  as  if  it  were
               equivalent to `$<:q', tcsh does not.  Furthermore,
               when tcsh is waiting for a line to  be  typed  the
               user  may  type  an  interrupt  to  interrupt  the
               sequence into which the line is to be substituted,
               but csh does not allow this.

       The  editor  command  expand-variables,  normally bound to
       `^X-$', can be used  to  interactively  expand  individual
       variables.

   Command, filename and directory stack substitution
       The remaining substitutions are applied selectively to the
       arguments of builtin commands.  This means  that  portions
       of  expressions  which are not evaluated are not subjected
       to these expansions.  For commands which are not  internal
       to  the  shell, the command name is substituted separately
       from the argument list.   This  occurs  very  late,  after
       input-output  redirection  is performed, and in a child of
       the main shell.

   Command substitution
       Command substitution is indicated by a command enclosed in
       ``'.   The output from such a command is broken into sepa­
       rate words at blanks, tabs and newlines,  and  null  words
       are discarded.  The output is variable and command substi­
       tuted and put in place of the original string.

       Command substitutions inside double  quotes  (`"')  retain
       blanks  and tabs; only newlines force new words.  The sin­
       gle final newline does not force a new word in  any  case.
       It  is  thus  possible for a command substitution to yield
       only part of a word, even if the command  outputs  a  com­
       plete line.

   Filename substitution
       If  a word contains any of the characters `*', `?', `[' or
       `{' or begins with the character `~' it is a candidate for
       filename  substitution,  also known as ``globbing''.  This
       word is then regarded as a pattern (``glob-pattern''), and
       replaced  with an alphabetically sorted list of file names
       which match the pattern.

       In matching filenames, the character `.' at the  beginning

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns which do not use `?', `*', or `[]' or  which
       use `{}' or `~' (below) are not negated correctly.

       The  metanotation  `a{b,c,d}e' is a shorthand for `abe ace
       ade'.      Left-to-right     order      is      preserved:
       `/usr/source/s1/{oldls,ls}.c'          expands          to
       `/usr/source/s1/oldls.c /usr/source/s1/ls.c'.  The results
       of  matches  are  sorted separately at a low level to pre­
       serve  this  order:  `../{memo,*box}'  might   expand   to
       `../memo  ../box  ../mbox'.   (Note  that  `memo'  was not
       sorted with the results of matching `*box'.)  It is not an
       error  when  this  construct expands to files which do not
       exist, but it is possible to get an error from  a  command
       to  which the expanded list is passed.  This construct may
       be nested.  As a special case the words `{', `}' and  `{}'
       are passed undisturbed.

       The character `~' at the beginning of a filename refers to
       home directories.  Standing alone, i.e., `~',  it  expands
       to  the invoker's home directory as reflected in the value
       of the home shell variable.  When followed by a name  con­
       sisting  of  letters,  digits and `-' characters the shell
       searches for a user with that name and  substitutes  their
       home directory; thus `~ken' might expand to `/usr/ken' and
       `~ken/chmach' to `/usr/ken/chmach'.  If the character  `~'
       is  followed  by a character other than a letter or `/' or
       appears elsewhere than at the beginning of a word,  it  is
       left   undisturbed.    A   command  like  `setenv  MANPATH
       /usr/man:/usr/local/man:~/lib/man' does not, therefore, do
       home directory substitution as one might hope.

       It is an error for a glob-pattern containing `*', `?', `['
       or `~', with or without `^', not to match any files.  How­
       ever,  only  one  pattern  in a list of glob-patterns must
       match a file (so that, e.g., `rm *.a *.c *.o'  would  fail
       only  if there were no files in the current directory end­
       ing in `.a', `.c', or `.o'), and if  the  nonomatch  shell
       variable  is  set  a  pattern  (or list of patterns) which
       matches nothing is left unchanged rather than  causing  an
       error.

       The  noglob  shell variable can be set to prevent filename
       substitution, and the expand-glob editor command, normally
       bound to `^X-*', can be used to interactively expand indi­
       vidual filename substitutions.


           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           /usr/spool/uucp
           > echo =0/calendar
           /usr/bin/calendar
           > echo =-
           /usr/accts/sys

       The noglob and nonomatch shell variables and  the  expand-
       glob  editor  command  apply to directory stack as well as
       filename substitutions.

   Other substitutions (+)
       There are several  more  transformations  involving  file­
       names,  not  strictly  related  to the above but mentioned
       here for completeness.  Any filename may be expanded to  a
       full  path  when  the  symlinks  variable (q.v.) is set to
       `expand'.  Quoting prevents this expansion, and  the  nor­
       malize-path editor command does it on demand.  The normal­
       ize-command editor command expands commands in  PATH  into
       full paths on demand.  Finally, cd and pushd interpret `-'
       as the old working  directory  (equivalent  to  the  shell
       variable  owd).  This is not a substitution at all, but an
       abbreviation recognized by only those commands.   Nonethe­
       less, it too can be prevented by quoting.

   Commands
       The  next  three  sections describe how the shell executes
       commands and deals with their input and output.

   Simple commands, pipelines and sequences
       A simple command is a sequence  of  words,  the  first  of
       which  specifies  the command to be executed.  A series of
       simple commands joined by `|' characters forms a pipeline.
       The  output  of each command in a pipeline is connected to
       the input of the next.

       Simple commands and pipelines may be joined into sequences
       with `;', and will be executed sequentially.  Commands and
       pipelines can also be joined into sequences with  `||'  or
       `&&', indicating, as in the C language, that the second is
       to be executed only if the first fails or succeeds respec­
       tively.

       A  simple  command,  pipeline or sequence may be placed in
       parentheses, `()', to form a simple command, which may  in
       turn be a component of a pipeline or sequence.  A command,
       pipeline or sequence can be executed without  waiting  for
           cd; pwd

       leaves  you in the home directory.  Parenthesized commands
       are most often used to prevent cd from affecting the  cur­
       rent shell.

       When a command to be executed is found not to be a builtin
       command the shell attempts  to  execute  the  command  via
       execve(2).   Each word in the variable path names a direc­
       tory in which the shell will look for the command.  If  it
       is  given  neither  a -c nor a -t option, the shell hashes
       the names in these directories into an internal  table  so
       that  it  will  try an execve(2) in only a directory where
       there is a possibility that  the  command  resides  there.
       This  greatly  speeds command location when a large number
       of directories are present in the search  path.   If  this
       mechanism  has  been turned off (via unhash), if the shell
       was given a -c or -t argument or  in  any  case  for  each
       directory  component  of  path which does not begin with a
       `/', the shell concatenates the current working  directory
       with  the given command name to form a path name of a file
       which it then attempts to execute.

       If the file has execute permissions but  is  not  an  exe­
       cutable  to  the system (i.e., it is neither an executable
       binary nor a script that specifies its interpreter),  then
       it is assumed to be a file containing shell commands and a
       new shell is spawned to read it.  The shell special  alias
       may  be set to specify an interpreter other than the shell
       itself.

       On systems which do not understand the `#!' script  inter­
       preter convention the shell may be compiled to emulate it;
       see the version shell variable.  If so, the  shell  checks
       the  first  line  of  the file to see if it is of the form
       `#!interpreter arg ...'.   If  it  is,  the  shell  starts
       interpreter  with  the given args and feeds the file to it
       on standard input.

   Input/output
       The standard input and standard output of a command may be
       redirected with the following syntax:

       < name  Open  file  name (which is first variable, command
               and filename expanded) as the standard input.
       << word Read the shell input up to a line which is identi­
               cal  to  word.  word is not subjected to variable,
               filename or command substitution, and  each  input
               line  is compared to word before any substitutions
               are done on this input  line.   Unless  a  quoting
               `\',  `"',  `' or ``' appears in word variable and
               command substitution is performed on the interven­

               If  the  shell variable noclobber is set, then the
               file must not exist or be a character special file
               (e.g.,  a  terminal  or  `/dev/null')  or an error
               results.  This helps prevent  accidental  destruc­
               tion  of files.  In this case the `!' forms can be
               used to suppress this check.

               The forms involving `&' route the diagnostic  out­
               put  into  the specified file as well as the stan­
               dard output.  name is expanded in the same way  as
               `<' input filenames are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like  `>',  but appends output to the end of name.
               If the shell variable noclobber is set, then it is
               an  error for the file not to exist, unless one of
               the `!' forms is given.

       A command receives the environment in which the shell  was
       invoked as modified by the input-output parameters and the
       presence of the command in a pipeline.  Thus, unlike  some
       previous  shells,  commands  run from a file of shell com­
       mands have no access  to  the  text  of  the  commands  by
       default;  rather  they receive the original standard input
       of the shell.  The `<<' mechanism should be used  to  pre­
       sent  inline  data.  This permits shell command scripts to
       function as components of pipelines and allows  the  shell
       to  block  read its input.  Note that the default standard
       input for a command run detached is  not  the  empty  file
       /dev/null,  but  the original standard input of the shell.
       If this is a terminal and if the process attempts to  read
       from  the  terminal,  then  the process will block and the
       user will be notified (see Jobs).

       Diagnostic output may be directed through a pipe with  the
       standard  output.   Simply  use  the form `|&' rather than
       just `|'.

       The shell  cannot  presently  redirect  diagnostic  output
       without  also redirecting standard output, but `(command >
       output-file)  >&  error-file'  is  often   an   acceptable
       workaround.   Either  output-file  or  error-file  may  be
       `/dev/tty' to send output to the terminal.

   Features
       Having described how the shell accepts,  parses  and  exe­
       cutes  command lines, we now turn to a variety of its use­
       ful features.

       input  whenever a loop is being read and performs seeks in
       this internal buffer to accomplish the  rereading  implied
       by  the  loop.   (To the extent that this allows, backward
       gotos will succeed on non-seekable inputs.)

   Expressions
       The if, while and exit builtin  commands  use  expressions
       with  a common syntax.  The expressions can include any of
       the operators described in the next three sections.   Note
       that  the  @  builtin  command (q.v.) has its own separate
       syntax.

   Logical, arithmetical and comparison operators
       These operators are similar to those of  C  and  have  the
       same precedence.  They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here the precedence increases to the right, `==' `!=' `=~'
       and `!~', `<=' `>=' `<' and `>', `<<' and  `>>',  `+'  and
       `-',  `*' `/' and `%' being, in groups, at the same level.
       The `==' `!=' `=~' and `!~' operators compare their  argu­
       ments  as  strings;  all  others  operate on numbers.  The
       operators `=~' and `!~' are like `!=' and `==' except that
       the  right  hand side is a glob-pattern (see Filename sub­
       stitution) against which the left hand operand is matched.
       This  reduces  the need for use of the switch builtin com­
       mand in shell scripts when all that is  really  needed  is
       pattern matching.

       Strings which begin with `0' are considered octal numbers.
       Null or missing arguments are considered `0'.  The results
       of  all  expressions  are strings, which represent decimal
       numbers.  It is important to note that no  two  components
       of  an expression can appear in the same word; except when
       adjacent to components of expressions which are  syntacti­
       cally  significant to the parser (`&' `|' `<' `>' `(' `)')
       they should be surrounded by spaces.

   Command exit status
       Commands can be executed in  expressions  and  their  exit
       status  returned  by  enclosing  them  in  braces  (`{}').
       Remember that the braces  should  be  separated  from  the
       words  of  the command by spaces.  Command executions suc­
       ceed, returning true, i.e., `1', if the command exits with
       status 0, otherwise they fail, returning false, i.e., `0'.
       If more detailed status information is required  then  the
       command  should  be  executed outside of an expression and
       the status shell variable examined.

   File inquiry operators
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)
           g   Set-group-ID bit is set (+)
           k   Sticky bit is set (+)
           t   file (which must be  a  digit)  is  an  open  file
               descriptor for a terminal device (+)
           R   Has been migrated (convex only) (+)
           L   Applies  subsequent operators in a multiple-opera­
               tor test to a symbolic link  rather  than  to  the
               file to which the link points (+) *

       file  is  command and filename expanded and then tested to
       see if it has the specified relationship to the real user.
       If  file  does  not  exist  or is inaccessible or, for the
       operators indicated by `*', if  the  specified  file  type
       does  not  exist on the current system, then all enquiries
       return false, i.e., `0'.

       These operators may  be  combined  for  conciseness:  `-xy
       file'  is  equivalent  to  `-x  file && -y file'.  (+) For
       example, `-fx' is true (returns `1') for plain  executable
       files, but not for directories.

       L  may be used in a multiple-operator test to apply subse­
       quent operators to a symbolic link rather than to the file
       to which the link points.  For example, `-lLo' is true for
       links owned by the invoking  user.   Lr,  Lw  and  Lx  are
       always  true  for  links and false for non-links.  L has a
       different meaning when it is the last operator in a multi­
       ple-operator test; see below.

       It  is  possible but not useful, and sometimes misleading,
       to combine operators which expect file to be a  file  with
       operators which do not, (e.g., X and t).  Following L with
       a non-file  operator  can  lead  to  particularly  strange
       results.

       Other  operators  return other information, i.e., not just
       `0' or `1'.  (+) They have the same format as  before;  op
       may be one of

           A       Last  file  access time, as the number of sec­
                   onds since the epoch
           A:      Like A, but in timestamp  format,  e.g.,  `Fri
                   May 14 16:36:10 1993'
           M       Last file modification time
                   group  and  other,  `20' if by group only, and
                   `0' if by neither
           Pmode:  Like Pmode:, with leading zero
           U       Numeric userid
           U:      Username, or the numeric userid if  the  user­
                   name is unknown
           G       Numeric groupid
           G:      Groupname,  or  the  numeric  groupid  if  the
                   groupname is unknown
           Z       Size, in bytes

       Only one of these operators may appear in a multiple-oper­
       ator  test,  and  it  must be the last.  Note that L has a
       different meaning at the end of and elsewhere in a  multi­
       ple-operator  test.   Because  `0' is a valid return value
       for many of these operators, they do not return  `0'  when
       they fail: most return `-1', and F returns `:'.

       If  the shell is compiled with POSIX defined (see the ver­
       sion shell variable), the result  of  a  file  inquiry  is
       based  on  the  permission bits of the file and not on the
       result of the access(2) system call.  For example, if  one
       tests  a  file  with -w whose permissions would ordinarily
       allow writing but which is on a file system mounted  read-
       only, the test will succeed in a POSIX shell but fail in a
       non-POSIX shell.

       File inquiry operators can  also  be  evaluated  with  the
       filetest builtin command (q.v.) (+).

   Jobs
       The shell associates a job with each pipeline.  It keeps a
       table of current jobs, printed by the  jobs  command,  and
       assigns them small integer numbers.  When a job is started
       asynchronously with `&', the shell  prints  a  line  which
       looks like

           [1] 1234

       indicating  that  the job which was started asynchronously
       was job number 1 and had one  (top-level)  process,  whose
       process id was 1234.

       If you are running a job and wish to do something else you
       may hit the suspend key (usually `^Z'), which sends a STOP
       signal  to  the current job.  The shell will then normally
       indicate that the  job  has  been  `Suspended'  and  print
       another  prompt.   If  the listjobs shell variable is set,
       all jobs will be listed like the jobs builtin command;  if
       it  is  set  to `long' the listing will be in long format,
       like `jobs -l'.  You can then manipulate the state of  the
       suspended  job.  You can put it in the ``background'' with
       editing command.  (+)

       A job being run in the background stops  if  it  tries  to
       read  from  the  terminal.   Background  jobs are normally
       allowed to produce output, but this  can  be  disabled  by
       giving  the  command  `stty  tostop'.  If you set this tty
       option, then background jobs will stop when  they  try  to
       produce output like they do when they try to read input.

       There are several ways to refer to jobs in the shell.  The
       character `%' introduces a job name.  If you wish to refer
       to  job  number 1, you can name it as `%1'.  Just naming a
       job brings it to the foreground; thus `%1'  is  a  synonym
       for  `fg  %1',  bringing  job  1 back into the foreground.
       Similarly, saying `%1 &' resumes job 1 in the  background,
       just  like  `bg  %1'.  A job can also be named by an unam­
       biguous prefix of the string typed in to start  it:  `%ex'
       would  normally  restart  a  suspended ex(1) job, if there
       were only one suspended job  whose  name  began  with  the
       string  `ex'.   It  is  also possible to say `%?string' to
       specify a job whose text contains string, if there is only
       one such job.

       The  shell  maintains a notion of the current and previous
       jobs.  In output pertaining to jobs, the  current  job  is
       marked  with  a  `+' and the previous job with a `-'.  The
       abbreviations `%+', `%', and (by analogy with  the  syntax
       of  the  history  mechanism) `%%' all refer to the current
       job, and `%-' refers to the previous job.

       The job control mechanism requires that the stty(1) option
       `new'  be  set  on some systems.  It is an artifact from a
       `new' implementation of the tty driver which allows gener­
       ation  of  interrupt  characters from the keyboard to tell
       jobs to stop.  See stty(1) and the setty  builtin  command
       for details on setting options in the new tty driver.

   Status reporting
       The  shell  learns  immediately whenever a process changes
       state.  It normally informs you  whenever  a  job  becomes
       blocked  so that no further progress is possible, but only
       right before it prints a prompt.  This is done so that  it
       does  not  otherwise  disturb your work.  If, however, you
       set the shell variable notify, the shell will  notify  you
       immediately  of  changes  of  status  in  background jobs.
       There is also a shell command notify which marks a  single
       process  so  that  its  status changes will be immediately
       reported.  By default notify marks  the  current  process;
       simply  say  `notify'  after  starting a background job to
       mark it.

       When you try to leave the shell while  jobs  are  stopped,
       event list, to be executed by the shell at a given time.

       The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd
       Special  aliases can be set, respectively, to execute com­
       mands when the shell wants to  ring  the  bell,  when  the
       working  directory  changes, every tperiod minutes, before
       each prompt, before each command gets executed, after each
       command  gets  executed,  and  when a job is started or is
       brought into the foreground.

       The autologout shell variable can be set  to  log  out  or
       lock the shell after a given number of minutes of inactiv­
       ity.

       The mail shell variable can be set to check for  new  mail
       periodically.

       The  printexitvalue shell variable can be set to print the
       exit status of commands which exit  with  a  status  other
       than zero.

       The rmstar shell variable can be set to ask the user, when
       `rm *' is typed, if that is really what was meant.

       The time shell variable can be set  to  execute  the  time
       builtin  command  after the completion of any process that
       takes more than a given number of CPU seconds.

       The watch and who shell variables can  be  set  to  report
       when  selected  users  log  in or out, and the log builtin
       command reports on those users at any time.

   Native Language System support (+)
       The shell is eight bit clean (if so compiled; see the ver­
       sion  shell  variable)  and  thus  supports character sets
       needing this capability.  NLS support differs depending on
       whether  or not the shell was compiled to use the system's
       NLS (again, see version).  In either case, 7-bit ASCII  is
       the  default  for  character  classification  (e.g., which
       characters are printable) and sorting,  and  changing  the
       LANG  or LC_CTYPE environment variables causes a check for
       possible changes in these respects.

       When using the system's NLS, the setlocale(3) function  is
       called  to  determine appropriate character classification
       and sorting.  This function typically  examines  the  LANG
       and  LC_CTYPE  environment  variables; refer to the system
       documentation for further details.   When  not  using  the
       system's  NLS, the shell simulates it by assuming that the
       ISO 8859-1 character set is used whenever  either  of  the
       LANG  and  LC_CTYPE variables are set, regardless of their
       values.  Sorting is not affected for the simulated NLS.
       nor  control  characters)  are printed in the format \nnn.
       If the tty is not in 8 bit mode, other  8  bit  characters
       are printed by converting them to ASCII and using standout
       mode.  The shell never changes the 7/8 bit mode of the tty
       and  tracks  user-initiated  changes of 7/8 bit mode.  NLS
       users (or, for that matter, those who want to use  a  meta
       key)  may  need  to  explicitly  set the tty in 8 bit mode
       through the appropriate  stty(1)  command  in,  e.g.,  the
       ~/.login file.

   OS variant support (+)
       A  number  of new builtin commands are provided to support
       features  in  particular  operating  systems.    All   are
       described in detail in the Builtin commands section.

       On   systems   that  support  TCF  (aix-ibm370,  aix-ps2),
       getspath and setspath get and  set  the  system  execution
       path,  getxvers  and setxvers get and set the experimental
       version prefix  and  migrate  migrates  processes  between
       sites.  The jobs builtin prints the site on which each job
       is executing.

       Under Domain/OS, inlib adds shared libraries to  the  cur­
       rent  environment,  rootnode  changes the rootnode and ver
       changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris  CX/UX,  universe  sets  the
       universe.

       Under  Harris  CX/UX,  ucb or att runs a command under the
       specified universe.

       Under Convex/OS, warp prints or sets the universe.

       The VENDOR,  OSTYPE  and  MACHTYPE  environment  variables
       indicate  respectively  the  vendor,  operating system and
       machine type (microprocessor class or  machine  model)  of
       the system on which the shell thinks it is running.  These
       are particularly useful when sharing one's home  directory
       between several types of machines; one can, for example,

           set  path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in one's ~/.login and put executables  compiled  for  each
       machine in the appropriate directory.

       The  version  shell  variable  indicates what options were
       chosen when the shell was compiled.

       Note also the newgrp builtin, the afsuser  and  echo_style

       The shell exits on a hangup (see  also  the  logout  shell
       variable).   By  default, the shell's children do too, but
       the shell does not send them a hangup when it exits.   hup
       arranges for the shell to send a hangup to a child when it
       exits, and nohup sets a child to ignore hangups.

   Terminal management (+)
       The shell uses three different sets of terminal  (``tty'')
       modes: `edit', used when editing, `quote', used when quot­
       ing literal characters, and `execute', used when executing
       commands.  The shell holds some settings in each mode con­
       stant, so commands which leave the tty in a confused state
       do  not  interfere with the shell.  The shell also matches
       changes in the speed and padding of the tty.  The list  of
       tty modes that are kept constant can be examined and modi­
       fied with the setty builtin.  Note that although the  edi­
       tor  uses CBREAK mode (or its equivalent), it takes typed-
       ahead characters anyway.

       The echotc, settc and  telltc  commands  can  be  used  to
       manipulate  and  debug terminal capabilities from the com­
       mand line.

       On systems that support SIGWINCH or SIGWINDOW,  the  shell
       adapts  to  window  resizing automatically and adjusts the
       environment variables LINES and COLUMNS if  set.   If  the
       environment  variable TERMCAP contains li# and co# fields,
       the shell adjusts them to reflect the new window size.


REFERENCE

       The next sections of  this  manual  describe  all  of  the
       available  Builtin  commands,  Special aliases and Special
       shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @
       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints  the  values  of  all  shell
               variables.

               The second form assigns the value of expr to name.
               The third form assigns the value of  expr  to  the
               expr  are  optional.   Components  of expr must be
               separated by spaces.

       alias [name [wordlist]]
               Without arguments, prints all aliases.  With name,
               prints   the   alias  for  name.   With  name  and
               wordlist, assigns wordlist as the alias  of  name.
               wordlist  is  command  and  filename  substituted.
               name may not be `alias' or  `unalias'.   See  also
               the unalias builtin command.

       alloc   Shows  the amount of dynamic memory acquired, bro­
               ken down into used and free memory.  With an argu­
               ment  shows  the number of free and used blocks in
               each size category.  The categories start at  size
               8  and double at each step.  This command's output
               may vary  across  system  types,  because  systems
               other  than  the  VAX  may  use a different memory
               allocator.

       bg [%job ...]
               Puts the specified jobs  (or,  without  arguments,
               the  current  job) into the background, continuing
               each if it is stopped.  job may  be  a  number,  a
               string,  `',  `%',  `+'  or `-' as described under
               Jobs.

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without options, the first form  lists  all  bound
               keys  and  the  editor  command  to  which each is
               bound, the second form lists the editor command to
               which  key  is  bound and the third form binds the
               editor command command to key.  Options include:

               -l  Lists all editor commands and a short descrip­
                   tion of each.
               -d  Binds  all  keys  to the standard bindings for
                   the default editor.
               -e  Binds all keys to the standard GNU  Emacs-like
                   bindings.
               -v  Binds  all  keys  to  the  standard vi(1)-like
                   bindings.
               -a  Lists or changes key-bindings in the  alterna­
                   tive  key map.  This is the key map used in vi
                   command mode.
               -b  key is  interpreted  as  a  control  character
                   written ^character (e.g., `^A') or C-character
                   (e.g., `C-A'), a  meta  character  written  M-
                   character  (e.g., `M-A'), a function key writ­
                   ten  F-string  (e.g.,   `F-string'),   or   an
                   interpretation.
               --  Forces  a break from option processing, so the
                   next word is taken as key even  if  it  begins
                   with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key  may  be a single character or a string.  If a
               command is bound to a string, the first  character
               of the string is bound to sequence-lead-in and the
               entire string is bound to the command.

               Control characters in key can be literal (they can
               be typed by preceding them with the editor command
               quoted-insert, normally bound to `^V') or  written
               caret-character  style,  e.g.,  `^A'.   Delete  is
               written `^?'  (caret-question mark).  key and com­
               mand  can contain backslashed escape sequences (in
               the style of System V echo(1)) as follows:

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The ASCII character  corresponding  to
                           the octal number nnn

               `\' nullifies the special meaning of the following
               character, if it has any, notably `\' and `^'.

       break   Causes execution to resume after the  end  of  the
               nearest enclosing foreach or while.  The remaining
               commands on the current line are executed.  Multi-
               level breaks are thus possible by writing them all
               on one line.

       breaksw Causes a break from a switch, resuming  after  the
               endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A  synonym for the logout builtin command.  Avail­
               able only if the shell was so  compiled;  see  the
               version shell variable.

       case label:
               A  label in a switch statement as discussed below.
               With -p, prints the final  directory  stack,  just
               like  dirs.  The -l, -n and -v flags have the same
               effect on cd as on dirs, and they imply -p.  (+)

               See also the implicitcd shell variable.

       chdir   A synonym for the cd builtin command.

       complete [command  [word/pattern/list[:select]/[[suffix]/]
       ...]] (+)
               Without arguments, lists  all  completions.   With
               command, lists completions for command.  With com­
               mand and word etc., defines completions.

               command may be a full command name or a  glob-pat­
               tern  (see  Filename  substitution).  It can begin
               with `-' to indicate  that  completion  should  be
               used only when command is ambiguous.

               word  specifies which word relative to the current
               word is to be completed, and may  be  one  of  the
               following:

                   c   Current-word  completion.   pattern  is  a
                       glob-pattern which must match  the  begin­
                       ning  of  the  current word on the command
                       line.  pattern is ignored when  completing
                       the current word.
                   C   Like c, but includes pattern when complet­
                       ing the current word.
                   n   Next-word completion.  pattern is a  glob-
                       pattern  which must match the beginning of
                       the previous word on the command line.
                   N   Like n, but must match  the  beginning  of
                       the word two before the current word.
                   p   Position-dependent completion.  pattern is
                       a numeric range, with the same syntax used
                       to   index  shell  variables,  which  must
                       include the current word.

               list, the list of possible completions, may be one
               of the following:

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands  (builtin  or  external  com­
                           mands)
                   C       External commands which begin with the
                           supplied path prefix
                   d       Directories
                   D       Directories  which begin with the sup­
                           plied path prefix

                   u       Usernames
                   x       Like n, but prints select  when  list-
                           choices is used.
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select  is  an  optional  glob-pattern.  If given,
               words from only list that match select are consid­
               ered  and  the  fignore shell variable is ignored.
               The last three types of completion may not have  a
               select  pattern,  and x uses select as an explana­
               tory message when the list-choices editor  command
               is used.

               suffix  is  a single character to be appended to a
               successful completion.  If null, no  character  is
               appended.   If  omitted  (in which case the fourth
               delimiter  can  also  be  omitted),  a  slash   is
               appended  to  directories  and  a  space  to other
               words.

               Now for some examples.  Some  commands  take  only
               directories as arguments, so there's no point com­
               pleting plain files.

                   > complete cd 'p/1/d/'

               completes  only  the  first  word  following  `cd'
               (`p/1')  with  a directory.  p-type completion can
               also be used to narrow down command completion:

                   > co[^D]
                   complete compress
                   > complete -co* 'p/0/(compress)/'
                   > co[^D]
                   > compress

               This completion completes commands (words in posi­
               tion  0, `p/0') which begin with `co' (thus match­
               ing `co*') to `compress' (the  only  word  in  the
               list).   The  leading `-' indicates that this com­
               pletion is to be used  with  only  ambiguous  com­
               mands.

                   > complete find 'n/-user/u/'

               is an example of n-type completion.  Any word fol­
               lowing `find' and immediately following `-user' is
               completed from the list of users.


               These  complete  words  following   `alias'   with
               aliases, `man' with commands, and `set' with shell
               variables.  `true' doesn't have any options, so  x
               does  nothing  when  completion  is  attempted and
               prints `Truth has  no  options.'  when  completion
               choices are listed.

               Note that the man example, and several other exam­
               ples below, could just as well have used 'c/*'  or
               'n/*' as 'p/*'.

               Words  can  be completed from a variable evaluated
               at completion time,

                   > complete ftp 'p/1/$hostnames/'
                   > set hostnames = (rtfm.mit.edu  tesla.ee.cor­
                   nell.edu)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^C]
                   >  set hostnames = (rtfm.mit.edu tesla.ee.cor­
                   nell.edu uunet.uu.net)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

               or from a command run at completion time:

                   >   complete  kill  'p/*/`ps  |  awk  \{print\
                   \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note that the complete  command  does  not  itself
               quote  its arguments, so the braces, space and `$'
               in `{print $1}' must be quoted explicitly.

               One command can have multiple completions:

                   > complete dbx 'p/2/(core)/' 'p/*/c/'

               completes the second argument to  `dbx'  with  the
               word `core' and all other arguments with commands.
               Note that the positional completion  is  specified
               before  the next-word completion.  Because comple­
               tions are evaluated from left  to  right,  if  the
               next-word completion were specified first it would
               always match and the positional  completion  would
               never  be executed.  This is a common mistake when
               defining a completion.

               The select pattern is useful when a command  takes
               to  exclude precious source code from `rm' comple­
               tion.  Of course, one could  still  type  excluded
               names  manually  or override the completion mecha­
               nism using the complete-word-raw or  list-choices-
               raw editor commands (q.v.).

               The `C', `D', `F' and `T' lists are like `c', `d',
               `f' and `t' respectively, but they use the  select
               argument  in  a different way: to restrict comple­
               tion to files beginning  with  a  particular  path
               prefix.   For  example,  the Elm mail program uses
               `=' as an abbreviation for one's  mail  directory.
               One might use

                   > complete elm c@=@F:$HOME/Mail/@

               to  complete  `elm  -f  ='  as  if it were `elm -f
               ~/Mail/'.  Note that we used `@' instead of `/' to
               avoid  confusion  with the select argument, and we
               used `$HOME' instead of `~' because home directory
               substitution  works  at  only  the  beginning of a
               word.

               suffix is used to add a  nonstandard  suffix  (not
               space  or `/' for directories) to completed words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes  arguments  to `finger' from the list of
               users, appends an `@', and  then  completes  after
               the `@' from the `hostnames' variable.  Note again
               the order in which the completions are  specified.

               Finally, here's a complex example for inspiration:

                   > complete find \
                   ´n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   ´n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   ´n/-type/(b c d f l p s)/' \
                   ´c/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \
                   ´p/*/d/'

               This completes words following `-name',  `-newer',
               `-cpio' or `ncpio' (note the pattern which matches
               both) to files, words following `-exec'  or  `-ok'
               to commands, words following `user' and `group' to
               users and groups respectively and words  following
               `-fstype'  or  `-type'  to  members  of  the given
               Continues execution of the nearest enclosing while
               or foreach.  The rest of the commands on the  cur­
               rent line are executed.

       default:
               Labels the default case in a switch statement.  It
               should come after all case labels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The first form prints the  directory  stack.   The
               top  of  the  stack  is  at the left and the first
               directory in the stack is the  current  directory.
               With  -l, `~' or `~name' in the output is expanded
               explicitly to home or the  pathname  of  the  home
               directory for user name.  (+) With -n, entries are
               wrapped before they reach the edge of the  screen.
               (+)  With  -v,  entries  are printed one per line,
               preceded by their stack positions.   (+)  If  more
               than  one  of  -n  or -v is given, -v takes prece­
               dence.  -p is accepted but does nothing.

               With -S, the second form saves the directory stack
               to  filename as a series of cd and pushd commands.
               With -L, the shell sources filename, which is pre­
               sumably  a  directory  stack  file saved by the -S
               option or the savedirs mechanism.  In either case,
               dirsfile  is  used  if  filename  is not given and
               ~/.cshdirs is used if dirsfile is unset.

               Note that login shells do the equivalent of  `dirs
               -L'  on startup and, if savedirs is set, `dirs -S'
               before exiting.  Because only  ~/.tcshrc  is  nor­
               mally  sourced  before ~/.cshdirs, dirsfile should
               be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes each word to the shell's  standard  output,
               separated by spaces and terminated with a newline.
               The echo_style shell variable may be set  to  emu­
               late  (or  not)  the flags and escape sequences of
               the BSD and/or System  V  versions  of  echo;  see
               echo(1).

       echotc [-sv] arg ... (+)
               Exercises  the  terminal  capabilities  (see term­
               cap(5)) in args.  For example, 'echotc home' sends
               the  cursor to the home position, 'echotc cm 3 10'
               sends it to column 3 and row 10, and 'echotc ts 0;
               Termcap strings may contain wildcards  which  will
               not  echo correctly.  One should use double quotes
               when setting a shell variable to a terminal  capa­
               bility  string,  as  in the following example that
               places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With -s, nonexistent capabilities return the empty
               string  rather  than  causing  an error.  With -v,
               messages are verbose.

       else
       end
       endif
       endsw   See the description of the  foreach,  if,  switch,
               and while statements below.

       eval arg ...
               Treats  the  arguments  as  input to the shell and
               executes the resulting command(s) in  the  context
               of  the  current  shell.   This is usually used to
               execute commands generated as the result  of  com­
               mand  or  variable  substitution,  because parsing
               occurs before these  substitutions.   See  tset(1)
               for a sample use of eval.

       exec command
               Executes  the  specified  command  in place of the
               current shell.

       exit [expr]
               The shell exits either with the value of the spec­
               ified  expr  (an  expression,  as  described under
               Expressions) or, without expr, with the  value  of
               the status variable.

       fg [%job ...]
               Brings  the specified jobs (or, without arguments,
               the current job) into the  foreground,  continuing
               each  if  it  is  stopped.  job may be a number, a
               string, `', `%', `+' or  `-'  as  described  under
               Jobs.   See also the run-fg-editor editor command.

       filetest -op file ... (+)
               Applies op (which is a file  inquiry  operator  as
               described  under  File  inquiry operators) to each
               file and returns the results as a  space-separated
               list.


       getspath (+)
               Prints the system execution path.  (TCF only)

       getxvers (+)
               Prints  the  experimental  version  prefix.   (TCF
               only)

       glob wordlist
               Like  echo,  but no `\' escapes are recognized and
               words are delimited by null characters in the out­
               put.   Useful  for  programs which wish to use the
               shell to filename expand a list of words.

       goto word
               word is filename and command-substituted to  yield
               a  string  of the form `label'.  The shell rewinds
               its input as much as possible, searches for a line
               of  the form `label:', possibly preceded by blanks
               or tabs, and continues execution after that  line.

       hashstat
               Prints  a statistics line indicating how effective
               the internal hash table has been at locating  com­
               mands (and avoiding exec's).  An exec is attempted
               for each component of  the  path  where  the  hash
               function  indicates  a  possible  hit, and in each
               component which does not begin with a `/'.

               On machines without vfork(2), prints only the num­
               ber and size of hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The  first form prints the history event list.  If
               n is given only  the  n  most  recent  events  are
               printed  or  saved.   With -h, the history list is
               printed without leading numbers.  If -T is  speci­
               fied, timestamps are printed also in comment form.
               (This can be used to produce  files  suitable  for
               loading  with  'history -L' or 'source -h'.)  With
               -r, the order of printing  is  most  recent  first
               rather than oldest first.

               With -S, the second form saves the history list to
               filename.  If the first word of the savehist shell
               variable  is  set  to  a number, at most that many
               lines are saved.  If the second word  of  savehist
               is set to `merge', the history list is merged with
               the existing history file instead of replacing  it
               (if  there  is one) and sorted by time stamp.  (+)
               filename.

               Note that login shells do the equivalent of  `his­
               tory -L' on startup and, if savehist is set, `his­
               tory -S' before exiting.  Because  only  ~/.tcshrc
               is  normally  sourced  before ~/.history, histfile
               should be set in ~/.tcshrc rather than ~/.login.

               If histlit is set,  the  first  and  second  forms
               print  and  save  the literal (unexpanded) form of
               the history list.

               The last form clears the history list.

       hup [command] (+)
               With command, runs command such that it will  exit
               on  a  hangup signal and arranges for the shell to
               send it a hangup  signal  when  the  shell  exits.
               Note  that  commands may set their own response to
               hangups,  overriding  hup.   Without  an  argument
               (allowed in only a shell script), causes the shell
               to exit on a  hangup  for  the  remainder  of  the
               script.   See  also  Signal handling and the nohup
               builtin command.

       if (expr) command
               If expr (an expression, as described under Expres­
               sions)  evaluates  true, then command is executed.
               Variable substitution on command happens early, at
               the  same time it does for the rest of the if com­
               mand.  command must be a simple  command,  not  an
               alias,  a  pipeline, a command list or a parenthe­
               sized command list, but  it  may  have  arguments.
               Input/output  redirection  occurs  even if expr is
               false and command is thus not executed; this is  a
               bug.

       if (expr) then
       ...
       else if (expr2) then
       ...
       else
       ...
       endif   If the specified expr is true then the commands to
               the first else are executed; otherwise if expr2 is
               true then the commands to the second else are exe­
               cuted, etc.  Any number of else-if pairs are  pos­
               sible; only one endif is needed.  The else part is
               likewise optional.  (The words else and endif must
               appear  at  the  beginning  of input lines; the if
               must appear alone on its input line  or  after  an
               else.)
               signal (or, if none is given, the TERM (terminate)
               signal) to the specified jobs or  processes.   job
               may  be a number, a string, `', `%', `+' or `-' as
               described under Jobs.  Signals are either given by
               number  or  by name (as given in /usr/include/sig­
               nal.h, stripped of the prefix `SIG').  There is no
               default  job;  saying  just `kill' does not send a
               signal to the current job.  If  the  signal  being
               sent is TERM (terminate) or HUP (hangup), then the
               job or process is sent a CONT (continue) signal as
               well.  The third form lists the signal names.

       limit [-h] [resource [maximum-use]]
               Limits  the consumption by the current process and
               each process it creates to not individually exceed
               maximum-use on the specified resource.  If no max­
               imum-use is  given,  then  the  current  limit  is
               printed; if no resource is given, then all limita­
               tions are given.  If the -h  flag  is  given,  the
               hard  limits  are used instead of the current lim­
               its.  The hard limits impose a ceiling on the val­
               ues  of  the  current limits.  Only the super-user
               may raise the hard limits, but a user may lower or
               raise the current limits within the legal range.

               Controllable  resources currently include (if sup­
               ported by the OS):

               cputime
                      the maximum number  of  cpu-seconds  to  be
                      used by each process

               filesize
                      the  largest  single file which can be cre­
                      ated

               datasize
                      the maximum growth of the data+stack region
                      via  sbrk(2)  beyond the end of the program
                      text

               stacksize
                      the  maximum  size  of  the  automatically-
                      extended stack region

               coredumpsize
                      the size of the largest core dump that will
                      be created

               memoryuse
                      the maximum amount  of  physical  memory  a
                      process may have allocated to it at a given

               maxproc
                      the  maximum  number  of  simultaneous pro­
                      cesses for this user id

               sbsize the maximum size of socket buffer usage for
                      this user

               maximum-use  may  be given as a (floating point or
               integer) number followed by a scale  factor.   For
               all limits other than cputime the default scale is
               `k' or `kilobytes' (1024 bytes); a scale factor of
               `m'  or `megabytes' may also be used.  For cputime
               the default scaling is `seconds',  while  `m'  for
               minutes  or  `h'  for hours, or a time of the form
               `mm:ss' giving minutes and seconds may be used.

               For both resource names and scale  factors,  unam­
               biguous prefixes of the names suffice.

       log (+) Prints  the  watch  shell  variable and reports on
               each user indicated in watch  who  is  logged  in,
               regardless  of when they last logged in.  See also
               watchlog.

       login   Terminates a login shell,  replacing  it  with  an
               instance  of  /bin/login.  This  is one way to log
               off, included for compatibility with sh(1).

       logout  Terminates a login shell.   Especially  useful  if
               ignoreeof is set.

       ls-F [-switch ...] [file ...] (+)
               Lists  files  like  `ls  -F', but much faster.  It
               identifies each type of special file in the  list­
               ing with a special character:

               /   Directory
               *   Executable
               #   Block device
               %   Character device
               |   Named pipe (systems with named pipes only)
               =   Socket (systems with sockets only)
               @   Symbolic  link  (systems  with  symbolic links
                   only)
               +   Hidden directory (AIX only) or context  depen­
                   dent (HP/UX only)
               :   Network special (HP/UX only)

               If  the  listlinks shell variable is set, symbolic
               links are identified in more detail (on only  sys­
               tems that have them, of course):

               listflags  contains  an `x', in which case it acts
               like `ls -xF'.  ls-F passes its arguments to ls(1)
               if  it  is  given any switches, so `alias ls ls-F'
               generally does the right thing.

               The ls-F builtin can list  files  using  different
               colors  depending  on  the  filetype or extension.
               See the color  tcsh  variable  and  the  LS_COLORS
               environment variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The  first form migrates the process or job to the
               site specified or the default site  determined  by
               the system path.  The second form is equivalent to
               `migrate -site $$': it migrates the  current  pro­
               cess  to  the specified site.  Migrating the shell
               itself can cause unexpected behavior, because  the
               shell does not like to lose its tty.  (TCF only)

       newgrp [-] group (+)
               Equivalent   to   `exec  newgrp';  see  newgrp(1).
               Available only if the shell was so  compiled;  see
               the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to num­
               ber, or, without number, to 4.  With command, runs
               command  at the appropriate priority.  The greater
               the number, the less cpu the  process  gets.   The
               super-user  may specify negative priority by using
               `nice -number ...'.  Command is always executed in
               a  sub-shell,  and the restrictions placed on com­
               mands in simple if statements apply.

       nohup [command]
               With command,  runs  command  such  that  it  will
               ignore hangup signals.  Note that commands may set
               their own response to hangups,  overriding  nohup.
               Without  an  argument  (allowed  in  only  a shell
               script), causes the shell to  ignore  hangups  for
               the remainder of the script.  See also Signal han­
               dling and the hup builtin command.

       notify [%job ...]
               Causes the shell to notify the user asynchronously
               when  the status of any of the specified jobs (or,
               without %job, the current job) changes, instead of
               waiting  until  the  next prompt as is usual.  job
               may be a number, a string, `', `%', `+' or `-'  as
               described  under  Jobs.  See also the notify shell
               variable.
               interrupts are disabled anyway.

       popd [-p] [-l] [-n|-v] [+n]
               Without arguments, pops the  directory  stack  and
               returns  to  the new top directory.  With a number
               `+n', discards the n'th entry in the stack.

               Finally, all forms of popd print the final  direc­
               tory stack, just like dirs.  The pushdsilent shell
               variable can be set to prevent  this  and  the  -p
               flag  can  be  given to override pushdsilent.  The
               -l, -n and -v flags have the same effect  on  popd
               as on dirs.  (+)

       printenv [name] (+)
               Prints  the  names  and  values of all environment
               variables or, with name, the value of the environ­
               ment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without  arguments, exchanges the top two elements
               of the directory stack.  If  pushdtohome  is  set,
               pushd  without  arguments does `pushd ~', like cd.
               (+) With name, pushes the current  working  direc­
               tory onto the directory stack and changes to name.
               If name is `-' it is interpreted as  the  previous
               working  directory  (see  Filename  substitution).
               (+) If dunique is set, pushd removes any instances
               of  name from the stack before pushing it onto the
               stack.  (+) With a number `+n',  rotates  the  nth
               element  of  the  directory stack around to be the
               top element and changes to  it.   If  dextract  is
               set,  however,  `pushd +n' extracts the nth direc­
               tory, pushes it onto the  top  of  the  stack  and
               changes to it.  (+)

               Finally, all forms of pushd print the final direc­
               tory stack, just like dirs.  The pushdsilent shell
               variable  can  be  set  to prevent this and the -p
               flag can be given to  override  pushdsilent.   The
               -l,  -n and -v flags have the same effect on pushd
               as on dirs.  (+)

       rehash  Causes the internal hash table of the contents  of
               the  directories in the path variable to be recom­
               puted.  This is needed if new commands  are  added
               to  directories  in  path while you are logged in.
               This should be necessary only if you add  commands
               to  one  of  your own directories, or if a systems
               programmer changes the contents of one of the sys­
               tem  directories.   Also flushes the cache of home
               directories built by tilde expansion.

       sched [+]hh:mm command (+)
       sched -n (+)
               The first form prints  the  scheduled-event  list.
               The  sched shell variable may be set to define the
               format  in  which  the  scheduled-event  list   is
               printed.   The  second  form  adds  command to the
               scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes the shell to echo `It's eleven o'clock.' at
               11 AM.  The time may be in 12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go
                   home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A  relative  time  specification may not use AM/PM
               format.  The third form removes item  n  from  the
               event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico
                   -r1 -sother
                        2  Wed Apr  4 17:00  set prompt=[%h] It's
                   after 5; go home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico
                   -r1 -sother

               A command in the scheduled-event list is  executed
               just  before the first prompt is printed after the
               time when the command is scheduled.  It is  possi­
               ble  to miss the exact time when the command is to
               be run, but an overdue command will execute at the
               next  prompt.  A command which comes due while the
               shell is waiting for user input is executed  imme­
               diately.  However, normal operation of an already-
               running command will not be interrupted so that  a
               scheduled-event list element may be run.

               This mechanism is similar to, but not the same as,
               the at(1) command on some Unix systems.  Its major
               disadvantage  is  that it may not run a command at
               exactly the specified time.  Its  major  advantage
               is  that  because  sched  runs  directly  from the
               shell, it has access to shell variables and  other
               structures.   This provides a mechanism for chang­
               list.  The second  form  sets  name  to  the  null
               string.   The  third  form sets name to the single
               word.  The fourth form sets name to  the  list  of
               words in wordlist.  In all cases the value is com­
               mand and filename expanded.  If -r  is  specified,
               the value is set read-only.  If -f or -l are spec­
               ified, set only unique words keeping their  order.
               -f  prefers the first occurrence of a word, and -l
               the last.  The fifth form sets the index'th compo­
               nent  of name to word; this component must already
               exist.  The sixth form lists only the names of all
               shell  variables  that are read-only.  The seventh
               form makes name read-only, whether or not it has a
               value.   The  second  form  sets  name to the null
               string.  The eighth form is the same as the  third
               form, but make name read-only at the same time.

               These arguments can be repeated to set and/or make
               read-only multiple variables in a single set  com­
               mand.  Note, however, that variable expansion hap­
               pens for all arguments before any setting  occurs.
               Note  also  that  `=' can be adjacent to both name
               and word or separated from both by whitespace, but
               cannot  be adjacent to only one or the other.  See
               also the unset builtin command.

       setenv [name [value]]
               Without arguments, prints the names and values  of
               all  environment  variables.  Given name, sets the
               environment variable name  to  value  or,  without
               value, to the null string.

       setpath path (+)
               Equivalent to setpath(1).  (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path.  (TCF only)

       settc cap value (+)
               Tells the shell to believe that the terminal capa­
               bility cap (as  defined  in  termcap(5))  has  the
               value value.  No sanity checking is done.  Concept
               terminal users may have to `settc xn  no'  to  get
               proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls which tty modes (see Terminal management)
               the shell does not allow to change.  -d, -q or  -x
               tells setty to act on the `edit', `quote' or `exe­
               cute' set of tty modes respectively;  without  -d,
               -q or -x, `execute' is used.

               removes it if string is omitted.  (TCF only)

       shift [variable]
               Without arguments, discards argv[1] and shifts the
               members  of  argv to the left.  It is an error for
               argv not to be set or to have less than  one  word
               as  value.  With variable, performs the same func­
               tion on variable.

       source [-h] name [args ...]
               The shell reads and executes commands  from  name.
               The  commands  are not placed on the history list.
               If any args are given, they are  placed  in  argv.
               (+)  source  commands  may  be nested; if they are
               nested too deeply the shell may run  out  of  file
               descriptors.   An  error  in a source at any level
               terminates all nested source commands.   With  -h,
               commands are placed on the history list instead of
               being executed, much like `history -L'.

       stop %job|pid ...
               Stops the specified jobs or  processes  which  are
               executing in the background.  job may be a number,
               a string, `', `%', `+' or `-' as  described  under
               Jobs.  There is no default job; saying just `stop'
               does not stop the current job.

       suspend Causes the shell to stop in its tracks, much as if
               it  had  been sent a stop signal with ^Z.  This is
               most often used to stop shells started by su(1).

       switch (string)
       case str1:
           ...
           breaksw
       ...
       default:
           ...
           breaksw
       endsw   Each case label is successively  matched,  against
               the  specified  string  which is first command and
               filename expanded.  The file  metacharacters  `*',
               `?'  and  `[...]'  may be used in the case labels,
               which are  variable  expanded.   If  none  of  the
               labels  match  before  a `default' label is found,
               then the execution begins after the default label.
               Each  case label and the default label must appear
               at the beginning of a line.  The  command  breaksw
               causes  execution  to  continue  after  the endsw.
               Otherwise control may fall through case labels and
               default  labels  as in C.  If no label matches and
               there is no default, execution continues after the
               shell and its children.

       umask [value]
               Sets  the  file  creation  mask to value, which is
               given in octal.  Common values for  the  mask  are
               002,  giving  all access to the group and read and
               execute access to others, and 022, giving read and
               execute  access  to the group and others.  Without
               value, prints the current file creation mask.

       unalias pattern
               Removes all aliases  whose  names  match  pattern.
               `unalias  *'  thus removes all aliases.  It is not
               an error for nothing to be unaliased.

       uncomplete pattern (+)
               Removes all completions whose names match pattern.
               `uncomplete  *'  thus removes all completions.  It
               is not an error for nothing to be uncompleted.

       unhash  Disables use of the internal hash table  to  speed
               location of executed programs.

       universe universe (+)
               Sets  the  universe  to  universe.   (Masscomp/RTU
               only)

       unlimit [-h] [resource]
               Removes the  limitation  on  resource  or,  if  no
               resource  is  specified, all resource limitations.
               With  -h,  the  corresponding  hard   limits   are
               removed.  Only the super-user may do this.

       unset pattern
               Removes  all  variables whose names match pattern,
               unless they are read-only.  `unset *' thus removes
               all variables unless they are read-only; this is a
               bad idea.  It is not an error for  nothing  to  be
               unset.

       unsetenv pattern
               Removes  all  environment  variables  whose  names
               match pattern.   `unsetenv  *'  thus  removes  all
               environment  variables; this is a bad idea.  It is
               not an error for nothing to be unsetenved.

       ver [systype [command]] (+)
               Without arguments, prints SYSTYPE.  With  systype,
               sets  SYSTYPE  to  systype.  With systype and com­
               mand, executes command under systype.  systype may
               be `bsd4.3' or `sys5.3'.  (Domain/OS only)

               Reports all known instances of command,  including
               aliases, builtins and executables in path.

       which command (+)
               Displays  the command that will be executed by the
               shell after substitutions,  path  searching,  etc.
               The  builtin command is just like which(1), but it
               correctly reports tcsh aliases and builtins and is
               10  to  100 times faster.  See also the which-com­
               mand editor command.

       while (expr)
       ...
       end     Executes the commands between the  while  and  the
               matching   end   while  expr  (an  expression,  as
               described under Expressions)  evaluates  non-zero.
               while  and  end  must  appear alone on their input
               lines.  break and continue may be used  to  termi­
               nate  or  continue  the  loop prematurely.  If the
               input is a terminal,  the  user  is  prompted  the
               first time through the loop as with foreach.

   Special aliases (+)
       If  set,  each  of these aliases executes automatically at
       the indicated time.  They are all initially undefined.

       beepcmd Runs when the shell wants  to  ring  the  terminal
               bell.

       cwdcmd  Runs after every change of working directory.  For
               example, if the user is working  on  an  X  window
               system  using  xterm(1)  and a re-parenting window
               manager that supports title bars  such  as  twm(1)
               and does

                   >  alias  cwdcmd   'echo -n "^[]2;${HOST}:$cwd
                   ^G"'

               then the shell will change the title of  the  run­
               ning xterm(1) to be the name of the host, a colon,
               and the full current working directory.  A fancier
               way to do that is

                   >       alias       cwdcmd       'echo      -n
                   "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

               This will put the hostname and  working  directory
               on the title bar but only the hostname in the icon
               manager menu.

               Note that putting a cd, pushd or  popd  in  cwdcmd
               may  cause  an  infinite loop.  It is the author's
               mand  name  for  which help is sought is passed as
               sole argument.  For example, if one does

                   > alias helpcommand '\!:1 --help'

               then the help display of the command  itself  will
               be invoked, using the GNU help calling convention.
               Currently there is no easy way to account for var­
               ious calling conventions (e.g., the customary Unix
               `-h'), except by using a table of many commands.

       periodic
               Runs every tperiod minutes.  This provides a  con­
               venient  means  for  checking on common but infre­
               quent changes such as new mail.  For  example,  if
               one does

                   > set tperiod = 30
                   > alias periodic checknews

               then  the  checknews(1) program runs every 30 min­
               utes.  If periodic is set but tperiod is unset  or
               set to 0, periodic behaves like precmd.

       precmd  Runs  just  before  each  prompt  is printed.  For
               example, if one does

                   > alias precmd date

               then date(1) runs just before  the  shell  prompts
               for  each  command.   There  are no limits on what
               precmd can be set to do, but discretion should  be
               used.

       postcmd Runs before each command gets executed.

                   > alias postcmd  'echo -n "^[]2\;\!#^G"'

               then  executing  vi  foo.c  will  put  the command
               string in the xterm title bar.

       shell   Specifies the interpreter for  executable  scripts
               which  do  not  themselves specify an interpreter.
               The first word should be a full path name  to  the
               desired    interpreter    (e.g.,   `/bin/csh'   or
               `/usr/local/bin/tcsh').

   Special shell variables
       The variables described in this section have special mean­
       ing to the shell.

       The  shell  sets  addsuffix,  argv,  autologout,  command,
       automatically interconverts the different formats of  path
       and PATH.

       addsuffix (+)
               If set, filename completion adds `/' to the end of
               directories and a space to the end of normal files
               when they are matched exactly.  Set by default.

       afsuser (+)
               If  set,  autologout's  autolock  feature uses its
               value instead of the local username  for  kerberos
               authentication.

       ampm (+)
               If  set, all times are shown in 12-hour AM/PM for­
               mat.

       argv    The arguments to the shell.  Positional parameters
               are  taken  from  argv,  i.e., `$1' is replaced by
               `$argv[1]', etc.   Set  by  default,  but  usually
               empty in interactive shells.

       autocorrect (+)
               If  set,  the spell-word editor command is invoked
               automatically before each completion attempt.

       autoexpand (+)
               If  set,  the  expand-history  editor  command  is
               invoked   automatically   before  each  completion
               attempt.

       autolist (+)
               If set, possibilities are listed after an  ambigu­
               ous completion.  If set to `ambiguous', possibili­
               ties are listed only when no  new  characters  are
               added by completion.

       autologout (+)
               The  first  word is the number of minutes of inac­
               tivity before automatic logout.  The optional sec­
               ond  word  is  the number of minutes of inactivity
               before automatic locking.  When the shell automat­
               ically logs out, it prints `auto-logout', sets the
               variable logout to `automatic'  and  exits.   When
               the   shell   automatically  locks,  the  user  is
               required to enter his password to  continue  work­
               ing.   Five incorrect attempts result in automatic
               logout.  Set to `60' (automatic  logout  after  60
               minutes,  and  no locking) by default in login and
               superuser shells, but not if the shell  thinks  it
               is  running  under a window system (i.e., the DIS­
               PLAY environment variable is set), the  tty  is  a

       cdpath  A list of directories in which  cd  should  search
               for  subdirectories  if  they  aren't found in the
               current directory.

       color   If set, it enables color display for  the  builtin
               ls-F  and  it passes --color=auto to ls.  Alterna­
               tively, it can be set to only ls-F or only  ls  to
               enable  color  to only one command.  Setting it to
               nothing is equivalent to setting it to (ls-F  ls).

       colorcat
               If  set,  it enables color escape sequence for NLS
               message files.  And display colorful NLS messages.

       command (+)
               If  set, the command which was passed to the shell
               with the -c flag (q.v.).

       complete (+)
               If set to `enhance', completion  1)  ignores  case
               and  2) considers periods, hyphens and underscores
               (`.', `-' and  `_')  to  be  word  separators  and
               hyphens and underscores to be equivalent.

       continue (+)
               If  set to a list of commands, the shell will con­
               tinue the listed commands, instead of  starting  a
               new one.

       continue_args (+)
               Same as continue, but the shell will execute:

                   echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

       correct (+)
               If   set  to  `cmd',  commands  are  automatically
               spelling-corrected.  If set  to  `complete',  com­
               mands  are  automatically  completed.   If  set to
               `all', the entire command line is corrected.

       cwd     The full pathname of the current  directory.   See
               also the dirstack and owd shell variables.

       dextract (+)
               If set, `pushd +n' extracts the nth directory from
               the directory stack rather than rotating it to the
               top.

       dirsfile (+)
               The  default location in which `dirs -S' and `dirs
               -L' look for a history file.  If unset, ~/.cshdirs
               is  used.   Because  only  ~/.tcshrc  is  normally

       dspmbyte (+)
               If set to `euc', it enables  display  and  editing
               EUC-kanji(Japanese)  code.   If  set to `sjis', it
               enables display  and  editing  Shift-JIS(Japanese)
               code.   If  set  to `big5', it enables display and
               editing Big5(Chinese) code.  If set to `utf8',  it
               enables  display  and  editing Utf8(Unicode) code.
               If set to the following format, it enables display
               and editing of original multi-byte code format:

                   > set dspmbyte = 0000....(256 bytes)....0000

               The table requires just 256 bytes.  Each character
               of 256 characters corresponds (from left to right)
               to  the  ASCII  codes  0x00, 0x01, ... 0xff.  Each
               character is set to number 0,1,2 and 3.  Each num­
               ber has the following meaning:
                 0 ... not used for multi-byte characters.
                 1  ...  used  for the first byte of a multi-byte
               character.
                 2 ... used for the second byte of  a  multi-byte
               character.
                 3  ...  used  for both the first byte and second
               byte of a multi-byte character.

                 Example:
               If set to `001322',  the  first  character  (means
               0x00  of  the  ASCII  code)  and  second character
               (means 0x01 of ASCII code) are set to `0'.   Then,
               it is not used for multi-byte characters.  The 3rd
               character (0x02) is set to '2', indicating that it
               is used for the first byte of a multi-byte charac­
               ter.  The 4th character(0x03) is set '3'.   It  is
               used  for  both the first byte and the second byte
               of a multi-byte character.  The 5th and 6th  char­
               acters (0x04,0x05) are set to '2', indicating that
               they are used for the second byte of a  multi-byte
               character.

               The  GNU  fileutils  version  of ls cannot display
               multi-byte filenames without the -N ( --literal  )
               option.    If  you are using this version, set the
               second word of dspmbyte  to  "ls".   If  not,  for
               example, "ls-F -l" cannot display multi-byte file­
               names.
               are  then done selectively.  Set by the -x command
               line option.

       echo_style (+)
               The style of the echo builtin.  May be set to

               bsd     Don't echo a newline if the first argument
                       is `-n'.
               sysv    Recognize  backslashed escape sequences in
                       echo strings.
               both    Recognize both the  `-n'  flag  and  back­
                       slashed escape sequences; the default.
               none    Recognize neither.

               Set  by  default to the local system default.  The
               BSD and System V  options  are  described  in  the
               echo(1) man pages on the appropriate systems.

       edit (+)
               If  set,  the command-line editor is used.  Set by
               default in interactive shells.

       ellipsis (+)
               If set, the `%c'/`%.' and  `%C'  prompt  sequences
               (see  the  prompt shell variable) indicate skipped
               directories with an ellipsis (`...')   instead  of
               `/<skipped>'.

       fignore (+)
               Lists  file name suffixes to be ignored by comple­
               tion.

       filec   In tcsh, completion is always used and this  vari­
               able is ignored by default. If edit is unset, then
               the traditional csh completion is used.  If set in
               csh, filename completion is used.

       gid (+) The user's real group ID.

       group (+)
               The user's group name.

       histchars
               A  string value determining the characters used in
               History substitution (q.v.).  The first  character
               of  its  value is used as the history substitution
               character, replacing the  default  character  `!'.
               The  second  character  of  its value replaces the
               character `^' in quick substitutions.

       histdup (+)
               Controls handling of duplicate entries in the his­
               ing the  same  home  directory  between  different
               machines,  or  when  saving  separate histories on
               different terminals.  Because  only  ~/.tcshrc  is
               normally   sourced   before  ~/.history,  histfile
               should be set in ~/.tcshrc rather than ~/.login.

       histlit (+)
               If set, builtin and editor commands and the  save­
               hist  mechanism  use the literal (unexpanded) form
               of lines in the history list.  See also  the  tog­
               gle-literal-history editor command.

       history The  first  word  indicates  the number of history
               events to save.   The  optional  second  word  (+)
               indicates  the format in which history is printed;
               if not given, `%h\t%T\t%R\n' is used.  The  format
               sequences  are  described below under prompt; note
               the variable meaning of `%R'.   Set  to  `100'  by
               default.

       home    Initialized  to the home directory of the invoker.
               The filename expansion of `~' refers to this vari­
               able.

       ignoreeof
               If  set  to  the empty string or `0' and the input
               device is  a  terminal,  the  end-of-file  command
               (usually  generated  by the user by typing `^D' on
               an empty line) causes  the  shell  to  print  `Use
               "exit"  to  leave tcsh.' instead of exiting.  This
               prevents the shell from accidentally being killed.
               If set to a number n, the shell ignores n - 1 con­
               secutive end-of-files and exits on the  nth.   (+)
               If  unset, `1' is used, i.e., the shell exits on a
               single `^D'.

       implicitcd (+)
               If set, the shell treats a directory name typed as
               a command as though it were a request to change to
               that directory.  If set to verbose, the change  of
               directory  is echoed to the standard output.  This
               behavior is  inhibited  in  non-interactive  shell
               scripts, or for command strings with more than one
               word.  Changing directory  takes  precedence  over
               executing  a  like-named  command,  but it is done
               after alias  substitutions.   Tilde  and  variable
               expansions work as expected.

       inputmode (+)
               If set to `insert' or `overwrite', puts the editor
               into that input mode  at  the  beginning  of  each
               line.
               to  less  than  `2',  the shell will only keep the
               most recently killed string.

       listflags (+)
               If set to `x', `a'  or  `A',  or  any  combination
               thereof  (e.g.,  `xA'),  they are used as flags to
               ls-F, making it act like `ls -xF', `ls  -Fa',  `ls
               -FA' or a combination (e.g., `ls -FxA'): `a' shows
               all files (even if they start  with  a  `.'),  `A'
               shows  all  files  but `.' and `..', and `x' sorts
               across instead of down.  If  the  second  word  of
               listflags  is  set,  it  is  used  as  the path to
               `ls(1)'.

       listjobs (+)
               If set, all jobs are listed when  a  job  is  sus­
               pended.   If set to `long', the listing is in long
               format.

       listlinks (+)
               If set, the ls-F builtin command shows the type of
               file to which each symbolic link points.

       listmax (+)
               The maximum number of items which the list-choices
               editor command will list without asking first.

       listmaxrows (+)
               The maximum number of  rows  of  items  which  the
               list-choices editor command will list without ask­
               ing first.

       loginsh (+)
               Set by the shell if it is a login shell.   Setting
               or unsetting it within a shell has no effect.  See
               also shlvl.

       logout (+)
               Set by the  shell  to  `normal'  before  a  normal
               logout,  `automatic'  before  an automatic logout,
               and `hangup' if the shell was killed by  a  hangup
               signal (see Signal handling).  See also the autol­
               ogout shell variable.

       mail    The names of the files or directories to check for
               incoming   mail,   separated  by  whitespace,  and
               optionally preceded by  a  numeric  word.   Before
               each  prompt,  if 10 minutes have passed since the
               last check, the shell checks each  file  and  says
               `You  have new mail.' (or, if mail contains multi­
               ple files, `You have new mail in  name.')  if  the
               filesize  is  greater  than zero in size and has a
               for those systems which store mail in this manner,
               such as the Andrew Mail System.

               If  the  first word of mail is numeric it is taken
               as a different mail checking interval, in seconds.

               Under  very  rare  circumstances,  the  shell  may
               report `You have mail.' instead of `You  have  new
               mail.'

       matchbeep (+)
               If set to `never', completion never beeps.  If set
               to `nomatch', it  beeps  only  when  there  is  no
               match.   If set to `ambiguous, it beeps when there
               are multiple matches.  If set to  `notunique',  it
               beeps  when  there  is  one exact and other longer
               matches.  If unset, `ambiguous' is used.

       nobeep (+)
               If set, beeping is completely disabled.  See  also
               visiblebell.

       noclobber
               If set, restrictions are placed on output redirec­
               tion to insure that  files  are  not  accidentally
               destroyed  and  that  `>>'  redirections  refer to
               existing files, as described in  the  Input/output
               section.

       noding  If  set,  disable  the  printing of `DING!' in the
               prompt time specifiers at the change of hour.

       noglob  If set, Filename substitution and Directory  stack
               substitution  (q.v.)  are inhibited.  This is most
               useful in shell scripts which  do  not  deal  with
               filenames,  or  after a list of filenames has been
               obtained and further expansions are not desirable.

       nokanji (+)
               If  set and the shell supports Kanji (see the ver­
               sion shell variable), it is disabled so  that  the
               meta key can be used.

       nonomatch
               If set, a Filename substitution or Directory stack
               substitution  (q.v.)  which  does  not  match  any
               existing files is left untouched rather than caus­
               ing an error.  It is still an error for  the  sub­
               stitution  to  be  malformed, e.g., `echo [' still
               gives an error.

       nostat (+)
               used  by  cd  and  pushd.   See  also  the cwd and
               dirstack shell variables.

       path    A list of directories in which to  look  for  exe­
               cutable  commands.  A null word specifies the cur­
               rent directory.  If there is no path variable then
               only full path names will execute.  path is set by
               the shell at startup  from  the  PATH  environment
               variable  or, if PATH does not exist, to a system-
               dependent default something like  `(/usr/local/bin
               /usr/bsd /bin /usr/bin .)'.  The shell may put `.'
               first or last in path or omit it entirely  depend­
               ing  on how it was compiled; see the version shell
               variable.  A shell which is given neither  the  -c
               nor  the  -t  option  hashes  the  contents of the
               directories in path after  reading  ~/.tcshrc  and
               each  time  path is reset.  If one adds a new com­
               mand to a directory in path  while  the  shell  is
               active,  one may need to do a rehash for the shell
               to find it.

       printexitvalue (+)
               If set and an interactive  program  exits  with  a
               non-zero status, the shell prints `Exit status'.

       prompt  The  string  which  is printed before reading each
               command from the terminal.  prompt may include any
               of  the  following formatting sequences (+), which
               are replaced by the given information:

               %/  The current working directory.
               %~  The current working directory, but with  one's
                   home  directory  represented  by `~' and other
                   users' home directories represented by `~user'
                   as per Filename substitution.  `~user' substi­
                   tution happens only if the shell  has  already
                   used `~user' in a pathname in the current ses­
                   sion.
               %c[[0]n], %.[[0]n]
                   The trailing component of the current  working
                   directory, or n trailing components if a digit
                   n is given.  If n begins with `0', the  number
                   of  skipped  components  precede  the trailing
                   component(s) in the  format  `/<skipped>trail­
                   ing'.   If the ellipsis shell variable is set,
                   skipped  components  are  represented  by   an
                   ellipsis  so  the whole becomes `...trailing'.
                   `~' substitution is done as in `%~' above, but
                   the  `~'  component  is  ignored when counting
                   trailing components.
               %C  Like %c, but without `~' substitution.
               %h, %!, !
                   format, with seconds.
               %P  Like `%p', but in 24-hour format (but see  the
                   ampm shell variable).
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %j  The number of jobs.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears  from  the  end of the prompt to end of
                   the display or the end of the line.
               %$  Expands the shell or environment variable name
                   immediately after the `$'.
               %#  `>' (or the first character of the promptchars
                   shell variable) for normal users, `#' (or  the
                   second character of promptchars) for the supe­
                   ruser.
               %{string%}
                   Includes string as a literal escape  sequence.
                   It  should  be  used  only  to change terminal
                   attributes and  should  not  move  the  cursor
                   location.  This cannot be the last sequence in
                   prompt.
               %?  The return code of the command  executed  just
                   before the prompt.
               %R  In  prompt2,  the  status  of  the parser.  In
                   prompt3, the corrected  string.   In  history,
                   the history string.

               `%B', `%S', `%U' and `%{string%}' are available in
               only eight-bit-clean shells; see the version shell
               variable.

               The  bold,  standout  and  underline sequences are
               often used to distinguish a superuser shell.   For
               example,

                   >  set  prompt  =  "%m  [%h] %B[%@]%b [%/] you
                   rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               If  `%t',  `%@',  `%T', `%p', or `%P' is used, and
               noding is not  set,  then  print  `DING!'  on  the
               change of hour (i.e, `:00' minutes) instead of the
               actual time.

               `CORRECT>%R (y|n|e|a)? ' in interactive shells.

       promptchars (+)
               If set (to a two-character string), the `%#'  for­
               matting  sequence  in the prompt shell variable is
               replaced with the first character for normal users
               and the second character for the superuser.

       pushdtohome (+)
               If  set,  pushd  without arguments does `pushd ~',
               like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the  directory
               stack.

       recexact (+)
               If  set,  completion  completes  on an exact match
               even if a longer match is possible.

       recognize_only_executables (+)
               If set, command listing displays only files in the
               path that are executable.  Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is exe­
               cuted.

       rprompt (+)
               The string to print on the right-hand side of  the
               screen  (after  the command input) when the prompt
               is being displayed on the left.  It recognizes the
               same  formatting  characters  as  prompt.  It will
               automatically disappear and reappear as necessary,
               to  ensure  that command input isn't obscured, and
               will appear only if the prompt, command input, and
               itself  will  fit  together on the first line.  If
               edit isn't set, then rprompt will be printed after
               the prompt and before the command input.

       savedirs (+)
               If  set,  the shell does `dirs -S' before exiting.
               If the first word is set to a number, at most that
               many directory stack entries are saved.

       savehist
               If  set,  the shell does `history -S' before exit­
               ing.  If the first word is set  to  a  number,  at
               most  that many lines are saved.  (The number must
               be less than or equal to history.)  If the  second
               word is set to `merge', the history list is merged
               with the existing history file instead of  replac­
               non-builtin command  execution.)   Initialized  to
               the (system-dependent) home of the shell.

       shlvl (+)
               The  number of nested shells.  Reset to 1 in login
               shells.  See also loginsh.

       status  The status returned by the last  command.   If  it
               terminated  abnormally,  then 0200 is added to the
               status.  Builtin commands which fail  return  exit
               status `1', all other builtin commands return sta­
               tus `0'.

       symlinks (+)
               Can be set to several different values to  control
               symbolic link (`symlink') resolution:

               If  set to `chase', whenever the current directory
               changes to a directory containing a symbolic link,
               it  is  expanded to the real name of the directory
               to which the link points.  This does not work  for
               the user's home directory; this is a bug.

               If set to `ignore', the shell tries to construct a
               current directory relative to the  current  direc­
               tory before the link was crossed.  This means that
               cding through a symbolic link and then `cd  ..'ing
               returns  one  to  the  original  directory.   This
               affects only builtin commands and filename comple­
               tion.

               If  set  to  `expand', the shell tries to fix sym­
               bolic links by actually expanding arguments  which
               look  like  path names.  This affects any command,
               not just builtins.  Unfortunately, this  does  not
               work  for  hard-to-recognize  filenames,  such  as
               those embedded in command options.  Expansion  may
               be  prevented  by  quoting.  While this setting is
               usually the most convenient, it is sometimes  mis­
               leading  and  sometimes confusing when it fails to
               recognize an argument which should be expanded.  A
               compromise  is  to use `ignore' and use the editor
               command normalize-path (bound by default to  ^X-n)
               when necessary.

               Some  examples  are in order.  First, let's set up
               some play directories:

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dst

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to

               and  here's  the  behavior  with  symlinks  set to
               `expand'.

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to
                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ".."; echo $cwd
                   /tmp/from
                   > /bin/echo ..
                   /tmp/to
                   > /bin/echo ".."
                   ..

               Note that `expand' expansion 1)  works  just  like
               `ignore'  for builtins like cd, 2) is prevented by
               quoting,  and  3)  happens  before  filenames  are
               passed to non-builtin commands.

       tcsh (+)
               The  version  number  of  the  shell in the format
               `R.VV.PP', where `R' is the major release  number,
               `VV'  the current version and `PP' the patchlevel.

       term    The terminal type.  Usually  set  in  ~/.login  as
               described under Startup and shutdown.

       time    If  set  to a number, then the time builtin (q.v.)
               executes automatically after  each  command  which
               takes  more  than that many CPU seconds.  If there
               is a second word, it is used as  a  format  string
               for  the output of the time builtin.  (u) The fol­
               lowing sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu
                   seconds.
               %S  The time the process spent in kernel  mode  in
                   cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used
                   in Kbytes.
                   (waits).
               %c  The number of involuntary context switches.

               Only  the  first  four  sequences are supported on
               systems without BSD resource limit functions.  The
               default  time  format  is  `%Uu  %Ss  %E %P %X+%Dk
               %I+%Oio  %Fpf+%Ww'  for   systems   that   support
               resource  usage  reporting and `%Uu %Ss %E %P' for
               systems that do not.

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r  and  %s
               are  not  available,  but the following additional
               sequences are:

               %Y  The number of system calls performed.
               %Z  The number of pages which are  zero-filled  on
                   demand.
               %i  The  number  of times a process's resident set
                   size was increased by the kernel.
               %d  The number of times a process's  resident  set
                   size was decreased by the kernel.
               %l  The number of read system calls performed.
               %m  The number of write system calls performed.
               %p  The number of reads from raw disk devices.
               %q  The number of writes to raw disk devices.

               and  the  default  time  format  is `%Uu %Ss $E %P
               %I+%Oio %Fpf+%Ww'.  Note that the  CPU  percentage
               can be higher than 100% on multi-processors.

       tperiod (+)
               The  period, in minutes, between executions of the
               periodic special alias.

       tty (+) The name of the tty, or empty if not  attached  to
               one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If  set,  causes  the  words of each command to be
               printed, after history substitution (if any).  Set
               by the -v command line option.

       version (+)
               The  version  ID  stamp.   It contains the shell's
               version number (see tcsh), origin,  release  date,
               vendor,  operating system and machine (see VENDOR,
               OSTYPE and MACHTYPE) and a comma-separated list of
               options  which  were set at compile time.  Options
               which are set by default in the  distribution  are
               dtr Login shells drop DTR when exiting
               bye bye is a synonym for  logout  and  log  is  an
                   alternate name for watchlog
               al  autologout is enabled; default
               kan Kanji  is  used  if  appropriate  according to
                   locale  settings,  unless  the  nokanji  shell
                   variable is set
               sm  The system's malloc(3) is used
               hb  The  `#!<program>  <args>'  convention is emu­
                   lated when executing shell scripts
               ng  The newgrp builtin is available
               rh  The shell attempts to set the REMOTEHOST envi­
                   ronment variable
               afs The shell verifies your password with the ker­
                   beros server if  local  authentication  fails.
                   The  afsuser  shell  variable  or  the AFSUSER
                   environment variable override your local user­
                   name if set.

               An  administrator  may enter additional strings to
               indicate differences in the local version.

       visiblebell (+)
               If set, a screen flash is  used  rather  than  the
               audible bell.  See also nobeep.

       watch (+)
               A  list of user/terminal pairs to watch for logins
               and logouts.  If either the user is `any' all ter­
               minals  are  watched  for  the given user and vice
               versa.  Setting watch to `(any any)'  watches  all
               users and terminals.  For example,

                   set  watch  =  (george ttyd1 any console $user
                   any)

               reports activity of the user  `george'  on  ttyd1,
               any  user  on the console, and oneself (or a tres­
               passer) on any terminal.

               Logins and logouts are checked every 10 minutes by
               default, but the first word of watch can be set to
               a number to check  every  so  many  minutes.   For
               example,

                   set watch = (1 any any)

               reports  any  login/logout once every minute.  For
               the impatient, the log builtin command triggers  a
               watch  report at any time.  All current logins are
               reported (as with the log builtin) when  watch  is
               first set.
                   `local' if the login/logout was from the local
                   host.
               %m  The hostname of the  remote  host  up  to  the
                   first  `.'.  The full name is printed if it is
                   an IP address or an X Window System display.

               %M and %m are available on only systems that store
               the  remote  hostname in /etc/utmp.  If unset, `%n
               has %a %l from %m.' is used, or `%n has %a %l.' on
               systems which don't store the remote hostname.

       wordchars (+)
               A  list  of non-alphanumeric characters to be con­
               sidered part of a word by the forward-word,  back­
               ward-word   etc.,   editor  commands.   If  unset,
               `*?_-.[]~=' is used.


ENVIRONMENT

       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The number of columns in the terminal.  See Termi­
               nal management.

       DISPLAY Used  by  X Window System (see X(1)).  If set, the
               shell does not set autologout (q.v.).

       EDITOR  The pathname to a default editor.   See  also  the
               VISUAL  environment variable and the run-fg-editor
               editor command.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HOST (+)
               Initialized to the name of the  machine  on  which
               the  shell  is running, as determined by the geth­
               ostname(2) system call.

       HOSTTYPE (+)
               Initialized to the type of machine  on  which  the
               shell  is  running, as determined at compile time.
               This variable is obsolete and will be removed in a
               future version.

       HPATH (+)
               A colon-separated list of directories in which the
               run-help editor command looks for command documen­
               tation.

               a two-character variable name.  The variables with
               their associated defaults are:

                   no   0      Normal (non-filename) text
                   fi   0      Regular file
                   di   01;34  Directory
                   ln   01;36  Symbolic link
                   pi   33     Named pipe (FIFO)
                   so   01;35  Socket
                   do   01;35  Door
                   bd   01;33  Block device
                   cd   01;32  Character device
                   ex   01;32  Executable file
                   mi   (none) Missing file (defaults to fi)
                   or   (none) Orphaned symbolic  link  (defaults
                               to ln)
                   lc   ^[[    Left code
                   rc   m      Right code
                   ec   (none) End code (replaces lc+no+rc)

               You need to include only the variables you want to
               change from the default.

               File names can also be colorized based on filename
               extension.   This  is  specified  in the LS_COLORS
               variable  using  the  syntax  "*ext=string".   For
               example, using ISO 6429 codes, to color all C-lan­
               guage  source  files  blue   you   would   specify
               "*.c=34".  This would color all files ending in .c
               in blue (34) color.

               Control  characters  can  be  written  either   in
               C-style-escaped  notation, or in stty-like ^-nota­
               tion.  The C-style notation adds ^[ for Escape,  _
               for  a  normal  space character, and ? for Delete.
               In addition, the ^[ escape character can  be  used
               to override the default interpretation of ^[, ^, :
               and =.

               Each file will be  written  as  <lc>  <color-code>
               <rc>  <filename>  <ec>.  If the <ec> code is unde­
               fined, the sequence <lc> <no> <rc>  will  be  used
               instead.   This  is  generally  more convenient to
               use, but less general.  The left,  right  and  end
               codes  are provided so you don't have to type com­
               mon parts over and over again and to support weird
               terminals;  you  will generally not need to change
               them at all unless your terminal does not use  ISO
               6429 color sequences but a different system.

               If  your  terminal  does use ISO 6429 color codes,
               you can compose the type codes (i.e.,  all  except
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background

               Not  all commands will work on all systems or dis­
               play devices.

               A few  terminal  programs  do  not  recognize  the
               default  end code properly.  If all text gets col­
               orized after  you  do  a  directory  listing,  try
               changing the no and fi codes from 0 to the numeri­
               cal codes for your standard fore-  and  background
               colors.

       MACHTYPE (+)
               The  machine type (microprocessor class or machine
               model), as determined at compile time.

       NOREBIND (+)
               If set, printable characters are  not  rebound  to
               self-insert-command.   See  Native Language System
               support.

       OSTYPE (+)
               The operating system,  as  determined  at  compile
               time.

       PATH    A  colon-separated list of directories in which to
               look for  executables.   Equivalent  to  the  path
               shell variable, but in a different format.

       PWD (+) Equivalent to the cwd shell variable, but not syn­
               chronized to it;  updated  only  after  an  actual
               directory change.

       REMOTEHOST (+)
               The  host  from  which  the  user  has  logged  in
               remotely, if this is the case  and  the  shell  is
               able  to  determine it.  Set only if the shell was
               so compiled; see the version shell variable.

       SHLVL (+)
               Equivalent to the shlvl shell variable.

       SYSTYPE (+)
               fg-editor editor command.


FILES

       /etc/csh.cshrc  Read  first  by  every  shell.   ConvexOS,
                       Stellix and Intel use /etc/cshrc and NeXTs
                       use  /etc/cshrc.std.  A/UX, AMIX, Cray and
                       IRIX have no  equivalent  in  csh(1),  but
                       read  this  file  in tcsh anyway.  Solaris
                       2.x does not  have  it  either,  but  tcsh
                       reads /etc/.cshrc.  (+)
       /etc/csh.login  Read by login shells after /etc/csh.cshrc.
                       ConvexOS,   Stellix    and    Intel    use
                       /etc/login,   NeXTs   use  /etc/login.std,
                       Solaris 2.x  uses  /etc/.login  and  A/UX,
                       AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read  by  every shell after /etc/csh.cshrc
                       or its equivalent.
       ~/.cshrc        Read by every shell, if ~/.tcshrc  doesn't
                       exist, after /etc/csh.cshrc or its equiva­
                       lent.  This  manual  uses  `~/.tcshrc'  to
                       mean  `~/.tcshrc  or,  if ~/.tcshrc is not
                       found, ~/.cshrc'.
       ~/.history      Read by login shells  after  ~/.tcshrc  if
                       savehist is set, but see also histfile.
       ~/.login        Read  by  login  shells after ~/.tcshrc or
                       ~/.history.  The shell may be compiled  to
                       read  ~/.login  before  instead  of  after
                       ~/.tcshrc and ~/.history; see the  version
                       shell variable.
       ~/.cshdirs (+)  Read  by  login  shells  after ~/.login if
                       savedirs is set, but see also dirsfile.
       /etc/csh.logout Read by login shells at logout.  ConvexOS,
                       Stellix  and  Intel  use  /etc/logout  and
                       NeXTs use  /etc/logout.std.   A/UX,  AMIX,
                       Cray   and  IRIX  have  no  equivalent  in
                       csh(1), but read this file in tcsh anyway.
                       Solaris  2.x  does not have it either, but
                       tcsh reads /etc/.logout.  (+)
       ~/.logout       Read  by  login  shells  at  logout  after
                       /etc/csh.logout or its equivalent.
       /bin/sh         Used to interpret shell scripts not start­
                       ing with a `#'.
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of  home  directories  for  `~name'
                       substitutions.

       The  order  in  which startup files are read may differ if
       the shell was so compiled; see Startup  and  shutdown  and
       the version shell variable.


NEW FEATURES (+)

       This manual describes tcsh as a single entity, but experi­
       Editor commands (q.v.) which perform  other  useful  func­
       tions  in the middle of typed commands, including documen­
       tation lookup (run-help), quick editor restarting (run-fg-
       editor) and command resolution (which-command).

       An enhanced history mechanism.  Events in the history list
       are time-stamped.  See also the history  command  and  its
       associated  shell  variables,  the previously undocumented
       `#' event specifier and new modifiers under  History  sub­
       stitution,  the  *-history,  history-search-*, i-search-*,
       vi-search-* and toggle-literal-history editor commands and
       the histlit shell variable.

       Enhanced  directory  parsing and directory stack handling.
       See the cd, pushd, popd and dirs commands and their  asso­
       ciated shell variables, the description of Directory stack
       substitution, the dirstack, owd and symlinks  shell  vari­
       ables  and the normalize-command and normalize-path editor
       commands.

       Negation in glob-patterns.  See Filename substitution.

       New File inquiry operators (q.v.) and a  filetest  builtin
       which uses them.

       A  variety  of Automatic, periodic and timed events (q.v.)
       including scheduled  events,  special  aliases,  automatic
       logout  and  terminal locking, command timing and watching
       for logins and logouts.

       Support for the Native Language System  (see  Native  Lan­
       guage System support), OS variant features (see OS variant
       support and the echo_style  shell  variable)  and  system-
       dependent file locations (see FILES).

       Extensive  terminal-management capabilities.  See Terminal
       management.

       New builtin commands including builtins, hup,  ls-F,  new­
       grp, printenv, which and where (q.v.).

       New  variables  that make useful information easily avail­
       able to the shell.  See  the  gid,  loginsh,  oid,  shlvl,
       tcsh,  tty,  uid and version shell variables and the HOST,
       REMOTEHOST, VENDOR, OSTYPE and MACHTYPE environment  vari­
       ables.

       A  new  syntax  for  including  useful  information in the
       prompt string (see prompt).  and special prompts for loops
       and spelling correction (see prompt2 and prompt3).

       Read-only variables.  See Variable substitution.
       c )'.

       Control  over  tty  output  after processes are started is
       primitive; perhaps this will inspire someone to work on  a
       good  virtual  terminal  interface.  In a virtual terminal
       interface much more interesting things could be done  with
       output control.

       Alias substitution is most often used to clumsily simulate
       shell procedures;  shell  procedures  should  be  provided
       rather than aliases.

       Commands  within loops are not placed in the history list.
       Control structures should be parsed rather than being rec­
       ognized  as  built-in  commands.  This would allow control
       commands to be placed anywhere, to be combined  with  `|',
       and to be used with `&' and `;' metasyntax.

       foreach doesn't ignore here documents when looking for its
       end.

       It should be possible to use the `:' modifiers on the out­
       put of command substitutions.

       The  screen  update for lines longer than the screen width
       is very poor if the terminal cannot  move  the  cursor  up
       (i.e., terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns which do not use `?', `*' or `[]'  or  which
       use `{}' or `~' are not negated correctly.

       The single-command form of if does output redirection even
       if the expression is false and the  command  is  not  exe­
       cuted.

       ls-F  includes file identification characters when sorting
       filenames and does not handle control characters in  file­
       names well.  It cannot be interrupted.

       Report bugs to tcsh-bugs@mx.gw.com, preferably with fixes.
       If you want to help maintain and test tcsh, send  mail  to
       listserv@mx.gw.com  with  the  text  `subscribe tcsh <your
       name>' on a line by itself in  the  body.   You  can  also
       `subscribe  tcsh-bugs <your name>' to get all bug reports,
       or `subscribe tcsh-diffs <your name>' to get the  develop­
       ment list plus diffs for each patchlevel.


THE T IN TCSH

       In  1964,  DEC produced the PDP-6.  The PDP-10 was a later
       re-implementation.  It was re-christened the  DECsystem-10
       for  PDP-10') objected; thus DEC found themselves support­
       ing two incompatible systems  on  the  same  hardware--but
       then there were 6 on the PDP-11!

       TENEX,  and  TOPS-20  to version 3, had command completion
       via a user-code-level subroutine  library  called  ULTCMD.
       With  version  3,  DEC  moved all that capability and more
       into the monitor (`kernel' for you Unix  types),  accessed
       by  the  COMND%  JSYS  (`Jump  to SYStem' instruction, the
       supervisor call mechanism [are my  IBM  roots  also  show­
       ing?]).

       The creator of tcsh was impressed by this feature and sev­
       eral others of TENEX and TOPS-20, and created a version of
       csh which mimicked them.


LIMITATIONS

       Words can be no longer than 1024 characters.

       The system limits argument lists to 10240 characters.

       The  number of arguments to a command which involves file­
       name expansion is limited to 1/6th the number  of  charac­
       ters allowed in an argument list.

       Command  substitutions  may  substitute no more characters
       than are allowed in an argument list.

       To detect looping, the shell restricts the number of alias
       substitutions on a single line to 20.


SEE ALSO

       csh(1),  emacs(1),  ls(1),  newgrp(1),  sh(1), setpath(1),
       stty(1),   su(1),   tset(1),   vi(1),   x(1),   access(2),
       execve(2),   fork(2),  killpg(2),  pipe(2),  setrlimit(2),
       sigvec(2),  stat(2),  umask(2),  vfork(2),  wait(2),  mal­
       loc(3),  setlocale(3), tty(4), a.out(5), termcap(5), envi­
       ron(7), termio(7), Introduction to the C Shell


VERSION

       This manual documents tcsh 6.12.00 (Astron) 2002-07-23.


AUTHORS

       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
         SHORT_STRINGS support and a new version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
         wordchars
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
         ~/.tcshrc
       Ray Moody, Purdue Physics, 1989
         Magic space bar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro  Honda,  Dept.  of Computer Science, Keio Univer­
       sity, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
         Extended key support
       Eric Schnoebelen, Convex, 1990
         Convex  support, lots of csh bug fixes, save and restore
         of directory stack
       Ron Flax, Apple, 1990
         A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
         NLS support and simulated NLS support for non NLS sites,
         fixes
       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi  mode fixes, expand-line, window change fixes, Symme­
         try port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist beeping options, modified the history search to
         search  for  the  whole string from the beginning of the
         line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking  process  group fixes, csh bug fixes, POSIX file
         tests, POSIX SIGHUP
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek, m88k, Titan and Masscomp ports  and  fixes.   Added
         autoconf support.
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
         Linux port
       Tim  P.  Starrin, NASA Langley Research Center Operations,
       1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New man page and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced  directory  printing  in prompt, added ellipsis
         and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported to WIN32 (Windows/95 and Windows/NT);  wrote  all
         the  missing  library and message catalog code to inter­
         face to Windows.
       Taga Nayuta, 1998
         Color ls additions.


THANKS TO

       Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson,
       Steve Romig, Diana Smetters, Bob Sutterfield, Mark Verber,
       Elizabeth Zwicky and all the other people  at  Ohio  State
       for suggestions and encouragement

       All  the people on the net, for putting up with, reporting
       bugs in, and suggesting new additions to  each  and  every
       version

       Richard  M. Alderson III, for writing the `T in tcsh' sec­
       tion

Astron 6.12.00             23 July 2002                   TCSH(1)

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