{"id":207,"date":"2020-08-18T19:23:47","date_gmt":"2020-08-18T20:23:47","guid":{"rendered":"http:\/\/www.linux-tutorial.info\/?page_id=77"},"modified":"2020-08-22T19:26:41","modified_gmt":"2020-08-22T20:26:41","slug":"this-is-the-page-title-toplevel-41","status":"publish","type":"page","link":"http:\/\/www.linux-tutorial.info\/?page_id=207","title":{"rendered":"vi Magic"},"content":{"rendered":"\nvi Magic<\/title>\n<p>\nI imagine that long before now, you have wondered how to turn on all that\nmagic I said that <command>vi<\/command> could do. Okay, let’s do it.\n<\/p>\n<p>\nThe first thing I want to talk about is abbreviations. You can tell vi that\nwhen you type in a specific set of characters it is supposed to automagically\nchange it to something else. For example, we could have <command>vi<\/command> always change “USA” to “United States of America”. This is done with the <filecontents type=\"\">abbr<\/filecontents> command.\n<\/p>\n<concept id=\"\" description=\"You can configure 'vi' to automatically change words as you type.\" \/>\n<question id=\"\" type=\"mc\" text=\"How would you create an abbreviation in 'vi' to always change 'CIA' to 'Central Intelligence Agency'?\" \/>\n<p>\nTo create a new abbreviation, you must get into ex-mode by pressing the\ncolon (:) in command mode. Next, type in abbr, followed by what you want to type\nin, and what vi should change it to. For example:\n<\/p>\n<p>\n<keyinput>:abbr USA United States of America<\/keyinput>\n<\/p>\n<p>\nNote that the abbreviation cannot contain any spaces because vi interprets\neverything after the second word as being part of the expansion.\n<\/p>\n<p>\nIf we later decide we don’t want that abbreviation anymore, we enter\n<\/p>\n<p>\n<keyinput>:unabbr USA<\/keyinput>\n<\/p>\n<p>\nBecause it is likely that we will want to use the abbreviation USA, it is\nnot a good idea to use an abbreviation that would normally occur, such as USA.\nIt would be better, instead, to use an abbreviation that doesn’t occur normally,\nlike Usa. Keep in mind, that abbreviations only apply to complete words.\nTherefore, something like the name “Sousa” won’t be translated to “SoUSA.” In\naddition, when your abbreviation is followed by a space, <keyinput>Tab<\/keyinput>, <keyinput>Enter<\/keyinput>, or <keyinput>Esc<\/keyinput>, the\nchange is made.\n<\/p>\n<p>\nLets take this one step further. What if we were always spelling “the” as\n“teh.” We could then create an abbreviation\n<\/p>\n<p>\n<keyinput>:abbr teh the<\/keyinput>\n<\/p>\n<concept id=\"\" description=\"With 'vi' you can configure a rudimentary spell checker.\" \/>\n<question id=\"\" type=\"tf\" text=\"The is no way in 'vi' to automatically correct frequently mispelled words.\" \/>\n<p>\nEvery time we misspell “the” as “teh,” vi would automatically correct it. If\nwe had a whole list of words that we regularly misspelled and created similar\nabbreviations, then every time we entered one of these misspelled words, it\nwould be replaced with the correctly spelled word. Wouldn’t that be automatic\nspell correction?\n<\/p>\n<question id=\"\" type=\"mc\" text=\"What key combination would you press in 'vi' ex-mode to ingore the meaning of special characters?\" \/>\n<concept id=\"\" description=\"In 'vi' ex-mode you use Ctrl-V to ingore the meaning of special characters.\" \/>\n<p>\nIf we ever want to “force” the spelling to be a particular way (that is,\nturn off the abbreviation momentarily), we simply follow the abbreviation with a\n<keyinput>Ctrl-V<\/keyinput>. This tells <command>vi<\/command> to ignore the special meaning of the following character.\nBecause the next character is a white space, which would force the expansion of\nthe abbreviation (which makes the white space special in this case), “turning\noff” the white space keeps the abbreviation from being expanded.\n<\/p>\n<concept id=\"\" description=\"You can also use vi to re-map certain key sequences.\" \/>\n<p>\nWe can also use vi to re-map certain sequences. For example, I have created\na command so that all I need to do to save a file is <keyinput>Ctrl-W <\/keyinput>(for <u>w<\/u>rite).\nIf I want to save the file and quit, I enter <keyinput>Ctrl-X<\/keyinput> with the “map” command.\n<\/p>\n<p>\nThe most common maps that I have seen have used control sequences, because\nmost of the other characters are already taken up. Therefore, we need to\nside-step a moment. First, we need to know how to\naccess <glossary term=\"control character\">control characters<\/glossary> from within vi. This is done in either command\nmode or input mode by first pressing <keyinput>Ctrl-V <\/keyinput>and then pressing the\n<glossary>control character<\/glossary> we want. So to get <keyinput>Ctrl-W<\/keyinput>, you would type\n<keyinput>Ctrl-V<\/keyinput>, then <keyinput>Ctrl-W<\/keyinput>. This would appear on the screen as ^W. This looks like two\ncharacters, but if you inserted it into a text file and moved\nover it with the <glossary>cursor<\/glossary>, you would realize that vi sees it\nas only one character. Note that although I pressed the lowercase w, it will\nappear as uppercase on the screen.\n<\/p>\n<p>\nSo, to map <keyinput>Ctrl-W<\/keyinput> so that every time we press it, we write our current file to disk, the command would be\n<\/p>\n<p>\n<keyinput>map ^W :w^M<\/keyinput>\n<\/p>\n<p>\nThis means that when we press <keyinput>Ctrl-W,<\/keyinput> vi interprets it as though we actually\ntyped <keyinput>:w<\/keyinput> and pressed Enter (the <keyinput>Ctrl-M<\/keyinput>: <keyinput>^M<\/keyinput>). The enter key at the end of the command\nis a good idea because you usually want the command to be executed right away.\nOtherwise, you would have to press Enter yourself.\n<\/p>\n<question id=\"\" type=\"tf\" text=\"In 'vi', you can map only control character and not function keys.\" \/>\n<concept id=\"\" description=\"In 'vi', you can map not only control character, but function keys, as well.\" \/>\n<p>\nAlso keep in mind that this can be used with the function keys. Because I am\naccustomed to many Windows applications in which the F2 key means to save, I map F2 to <keyinput>Ctrl-V<\/keyinput>, then <keyinput>F2<\/keyinput>. It looks like this:\n<\/p>\n<p>\n<keyinput>map ^[[N :w^M<\/keyinput> (The ^[[N is what the F2 key displays on the screen)\n<\/p>\n<p>\nIf we want, we can also use shifted function characters. Therefore, we can\nmap <keyinput>Shift-F2<\/keyinput> to something else. Or, for that matter, we can also use shifted and control function keys.\n<\/p>\n<p>\nIt has been my experience that, for the most part, if you use <keyinput>Shift<\/keyinput> and <keyinput>Ctrl<\/keyinput>\nwith non-function keys, vi only sees <keyinput>Ctrl<\/keyinput> and not <keyinput>Shift<\/keyinput>. Also, <keyinput>Alt<\/keyinput> may not work\nbecause on the system console, <keyinput>Alt<\/keyinput> plus a function key tells the system to switch to multiscreens.\n<\/p>\n<p>\nI try not to use the same key sequences that <command>vi<\/command> already does. First, it\nconfuses me because I often forget that I remapped something. Second, the real\nvi commands are then inaccessible. However, if you are used to a different\ncommand set (that is, from a different editor), you can “program” vi to behave\nlike that other editor.\n<\/p>\n<p>\nNever define a mapping that contains its own name, as this ends up\nrecursively expanding the abbreviation. The classic example is :map! n\nbanana. Every time you typed in the word “banana,” you’d get\n<\/p>\n<p>\n<screenoutput>bababababababababababababababababa…<\/screenoutput>\n<\/p>\n<p>\nand depending on what version you were running, vi would catch the fact that\nthis is an infinite translation and stop.\n","protected":false},"excerpt":{"rendered":"<p>vi Magic I imagine that long before now, you have wondered how to turn on all that magic I said that vi could do. Okay, let’s do it. The first thing I want to talk about is abbreviations. You can … <a href=\"http:\/\/www.linux-tutorial.info\/?page_id=207\">Continue reading <span class=\"meta-nav\">→<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-207","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/207","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=207"}],"version-history":[{"count":1,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/207\/revisions"}],"predecessor-version":[{"id":781,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/207\/revisions\/781"}],"wp:attachment":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=207"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}