setfacl
SYNOPSIS
setfacl [-bkndRLPvh] [{-m|-x} acl_spec] [{-M|-X} acl_file]
file ...
setfacl --restore=file
DESCRIPTION
This utility sets Access Control Lists (ACLs) of files and
directories. On the command line, a sequence of commands
is followed by a sequence of files (which in turn can be
followed by another sequence of commands, ...).
The options -m, and -x expect an ACL on the command line.
Multiple ACL entries are separated by comma characters
(`,'). The options -M, and -X read an ACL from a file or
from standard input. The ACL entry format is described in
Section ACL ENTRIES.
The --set and --set-file options set the ACL of a file or
a directory. The previous ACL is replaced. ACL entries
for this operation must include permissions.
The -m (--modify) and -M (--modify-file) options modify
the ACL of a file or directory. ACL entries for this
operation must include permissions.
The -x (--remove) and -X (--remove-file) options remove
ACL enries. Only ACL entries without the perms field are
accepted as parameters, unless POSIXLY_CORRECT is defined.
When reading from files using the -M, and -X options, set
facl accepts the output getfacl produces. There is at
most one ACL entry per line. After a Pound sign (`#'),
everything up to the end of the line is treated as a com
ment.
If setfacl is used on a file system which does not support
ACLs, setfacl operates on the file mode permission bits.
If the ACL does not fit completely in the permission bits,
setfacl modifies the file mode permission bits to reflect
the ACL as closely as possible, writes an error message to
standard error, and returns with an exit status greater
than 0.
PERMISSIONS
The file owner and processes capable of CAP_FOWNER are
granted the right to modify ACLs of a file. This is analo
gous to the permissions required for accessing the file
mode. (On current Linux systems, root is the only user
with the CAP_FOWNER capability.)
mask entry, unless a mask entry was explicitly given.
The mask entry is set to the union of all permissions
of the owning group, and all named user and group
entries. (These are exactly the entries affected by
the mask entry).
--mask
Do recalculate the effective rights mask, even if an
ACL mask entry was explicitly given. (See the -n
option.)
-d, --default
All operations apply to the Default ACL. Regular ACL
entries in the input set are promoted to Default ACL
entries. Default ACL entries in the input set are dis
carded. (A warning is issued if that happens).
--restore=file
Restore a permission backup created by `getfacl -R' or
similar. All permissions of a complete directory sub
tree are restored using this mechanism. If the input
contains owner comments or group comments, and setfacl
is run by root, the owner and owning group of all
files are restored as well. This option cannot be
mixed with other options except `--test'.
--test
Test mode. Instead of changing the ACLs of any files,
the resulting ACLs are listed.
-R, --recursive
Apply operations to all files and directories recur
sively. This option cannot be mixed with `--restore'.
-L, --logical
Logical walk, follow symbolic links. The default
behavior is to follow symbolic link arguments, and to
skip symbolic links encountered in subdirectories.
This option cannot be mixed with `--restore'.
-P, --physical
Physical walk, skip all symbolic links. This also
skips symbolic link arguments. This option cannot be
mixed with `--restore'.
--version
Print the version of setfacl and exit.
--help
Print help explaining the command line options.
-- End of command line options. All remaining parameters
file owner if uid is empty.
[d[efault]:] g[roup]:gid [:perms]
Permissions of a named group. Permissions of the
owning group if gid is empty.
[d[efault]:] m[ask][:] [:perms]
Effective rights mask
[d[efault]:] o[ther][:] [:perms]
Permissions of others.
Whitespace between delimiter characters and non-delimiter
characters is ignored.
Proper ACL entries including permissions are used in mod
ify and set operations. (options -m, -M, --set and --set-
file). Entries without the perms field are used for dele
tion of entries (options -x and -X).
For uid and gid you can specify either a name or a number.
The perms field is a combination of characters that indi
cate the permissions: read (r), write (w), execute (x),
execute only if the file is a directory or already has
execute permission for some user (X). Alternatively, the
perms field can be an octal digit (0-7).
AUTOMATICALLY CREATED ENTRIES
Initially, files and directories contain only the three
base ACL entries for the owner, the group, and others.
There are some rules that need to be satisfied in order
for an ACL to be valid:
* The three base entries cannot be removed. There must
be exactly one entry of each of these base entry
types.
* Whenever an ACL contains named user entries or named
group objects, it must also contain an effective
rights mask.
* Whenever an ACL contains any Default ACL entries, the
three Default ACL base entries (default owner, default
group, and default others) must also exist.
* Whenever a Default ACL contains named user entries or
named group objects, it must also contain a default
effective rights mask.
copy of the ACL owner, owning group, or others entry
is added to the Default ACL.
* If a Default ACL contains named user entries or named
group entries, and no mask entry exists, a mask entry
containing the same permissions as the default Default
ACL's group entry is added. Unless the -n option is
given, the permissions of the mask entry are further
adjusted to inclu de the union of all permissions
affected by the mask entry. (See the -n option
description).
EXAMPLES
Granting an additional user read access
setfacl -m u:lisa:r file
Revoking write access from all groups and all named users
(using the effective rights mask)
setfacl -m m::rx file
Removing a named group entry from a file's ACL
setfacl -x g:staff file
Copying the ACL of one file to another
getfacl file1 | setfacl --set-file=- file2
Copying the access ACL into the Default ACL
getfacl -a dir | setfacl -d -M- dir
CONFORMANCE TO POSIX 1003.1e DRAFT STANDARD 17
If the environment variable POSIXLY_CORRECT is defined,
the default behavior of setfacl changes as follows: All
non-standard options are disabled. The ``default:'' pre
fix is disabled. The -x and -X options also accept per
mission fields (and ignore them).
AUTHOR
Andreas Gruenbacher, <a.gruenbacher@computer.org>.
Please send your bug reports, suggested features and com
ments to the above address.
SEE ALSO
getfacl(1), chmod(1), umask(1), acl(5)
May 2000 ACL File Utilities SETFACL(1)
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