VIM: usr_20

## USR_20

    *usr_20.txt*	For Vim version 8.2.  Last change: 2021 Nov 18

    		     VIM USER MANUAL - by Bram Moolenaar

    		     Typing command-line commands quickly

    Vim has a few generic features that makes it easier to enter commands.  Colon
    commands can be abbreviated, edited and repeated.  Completion is available for
    nearly everything.

    |20.1|	Command line editing
    |20.2|	Command line abbreviations
    |20.3|	Command line completion
    |20.4|	Command line history
    |20.5|	Command line window

         Next chapter: |usr_21|  Go away and come back
     Previous chapter: |usr_12|  Clever tricks
    Table of contents: |usr_toc|

    *20.1*	Command line editing

    When you use a colon (:) command or search for a string with / or ?, Vim puts
    the cursor on the bottom of the screen.  There you type the command or search
    pattern.  This is called the Command line.  Also when it's used for entering a
    search command.

    The most obvious way to edit the command you type is by pressing the <BS> key.
    This erases the character before the cursor.  To erase another character,
    typed earlier, first move the cursor with the cursor keys.
       For example, you have typed this:

    	:s/col/pig/

    Before you hit <Enter>, you notice that "col" should be "cow".  To correct
    this, you type <Left> five times.  The cursor is now just after "col".  Type
    <BS> and "w" to correct:

    	:s/cow/pig/

    Now you can press <Enter> directly.  You don't have to move the cursor to the
    end of the line before executing the command.

    The most often used keys to move around in the command line:

    	<Left>			one character left
    	<Right>			one character right
    	<S-Left> or <C-Left>	one word left
    	<S-Right> or <C-Right>	one word right
    	CTRL-B or <Home>	to begin of command line
    	CTRL-E or <End>		to end of command line

    	Note:
    	<S-Left> (cursor left key with Shift key pressed) and <C-Left> (cursor
    	left key with Control pressed) will not work on all keyboards.  Same
    	for the other Shift and Control combinations.

    You can also use the mouse to move the cursor.

    DELETING

    As mentioned, <BS> deletes the character before the cursor.  To delete a whole
    word use CTRL-W.

    	/the fine pig

    		     CTRL-W

    	/the fine

    CTRL-U removes all text, thus allows you to start all over again.

    OVERSTRIKE

    The <Insert> key toggles between inserting characters and replacing the
    existing ones.  Start with this text:

    	/the fine pig

    Move the cursor to the start of "fine" with <S-Left> twice (or <Left> eight
    times, if <S-Left> doesn't work).  Now press <Insert> to switch to overstrike
    and type "great":

    	/the greatpig

    Oops, we lost the space.  Now, don't use <BS>, because it would delete the
    "t" (this is different from Replace mode).  Instead, press <Insert> to switch
    from overstrike to inserting, and type the space:

    	/the great pig

    CANCELLING

    You thought of executing a : or / command, but changed your mind.  To get rid
    of what you already typed, without executing it, press CTRL-C or <Esc>.

    	Note:
    	<Esc> is the universal "get out" key.  Unfortunately, in the good old
    	Vi pressing <Esc> in a command line executed the command!  Since that
    	might be considered to be a bug, Vim uses <Esc> to cancel the command.
    	But with the 'cpoptions' option it can be made Vi compatible.  And
    	when using a mapping (which might be written for Vi) <Esc> also works
    	Vi compatible.  Therefore, using CTRL-C is a method that always works.

    If you are at the start of the command line, pressing <BS> will cancel the
    command.  It's like deleting the ":" or "/" that the line starts with.

    *20.2*	Command line abbreviations

    Some of the ":" commands are really long.  We already mentioned that
    ":substitute" can be abbreviated to ":s".  This is a generic mechanism, all
    ":" commands can be abbreviated.

    How short can a command get?  There are 26 letters, and many more commands.
    For example, ":set" also starts with ":s", but ":s" doesn't start a ":set"
    command.  Instead ":set" can be abbreviated to ":se".
       When the shorter form of a command could be used for two commands, it
    stands for only one of them.  There is no logic behind which one, you have to
    learn them.  In the help files the shortest form that works is mentioned.  For
    example:

    	:s[ubstitute]

    This means that the shortest form of ":substitute" is ":s".  The following
    characters are optional.  Thus ":su" and ":sub" also work.

    In the user manual we will either use the full name of command, or a short
    version that is still readable.  For example, ":function" can be abbreviated
    to ":fu".  But since most people don't understand what that stands for, we
    will use ":fun".  (Vim doesn't have a ":funny" command, otherwise ":fun" would
    be confusing too.)

    It is recommended that in Vim scripts you write the full command name.  That
    makes it easier to read back when you make later changes.  Except for some
    often used commands like ":w" (":write") and ":r" (":read").
       A particularly confusing one is ":end", which could stand for ":endif",
    ":endwhile" or ":endfunction".  Therefore, always use the full name.

    SHORT OPTION NAMES

    In the user manual the long version of the option names is used.  Many options
    also have a short name.  Unlike ":" commands, there is only one short name
    that works.  For example, the short name of 'autoindent' is 'ai'.  Thus these
    two commands do the same thing:

    	:set autoindent
    	:set ai

    You can find the full list of long and short names here: |option-list|.

    *20.3*	Command line completion

    This is one of those Vim features that, by itself, is a reason to switch from
    Vi to Vim.  Once you have used this, you can't do without.

    Suppose you have a directory that contains these files:

    	info.txt
    	intro.txt
    	bodyofthepaper.txt

    To edit the last one, you use the command:

    	:edit bodyofthepaper.txt

    It's easy to type this wrong.  A much quicker way is:

    	:edit b<Tab>

    Which will result in the same command.  What happened?  The <Tab> key does
    completion of the word before the cursor.  In this case "b".  Vim looks in the
    directory and finds only one file that starts with a "b".  That must be the
    one you are looking for, thus Vim completes the file name for you.

    Now type:

    	:edit i<Tab>

    Vim will beep, and give you:

    	:edit info.txt

    The beep means that Vim has found more than one match.  It then uses the first
    match it found (alphabetically).  If you press <Tab> again, you get:

    	:edit intro.txt

    Thus, if the first <Tab> doesn't give you the file you were looking for, press
    it again.  If there are more matches, you will see them all, one at a time.
       If you press <Tab> on the last matching entry, you will go back to what you
    first typed:

    	:edit i

    Then it starts all over again.  Thus Vim cycles through the list of matches.
    Use CTRL-P to go through the list in the other direction:

    	      <------------------- <Tab> -------------------------+
    								  |
    		  <Tab> -->		       <Tab> -->
    	:edit i		      :edit info.txt		   :edit intro.txt
    		  <-- CTRL-P		       <-- CTRL-P
    	   |
    	   +---------------------- CTRL-P ------------------------>

    CONTEXT

    When you type ":set i" instead of ":edit i" and press <Tab> you get:

    	:set icon

    Hey, why didn't you get ":set info.txt"?  That's because Vim has context
    sensitive completion.  The kind of words Vim will look for depends on the
    command before it.  Vim knows that you cannot use a file name just after a
    ":set" command, but you can use an option name.
       Again, if you repeat typing the <Tab>, Vim will cycle through all matches.
    There are quite a few, it's better to type more characters first:

    	:set isk<Tab>

    Gives:

    	:set iskeyword

    Now type "=" and press <Tab>:

    	:set iskeyword=@,48-57,_,192-255

    What happens here is that Vim inserts the old value of the option.  Now you
    can edit it.
       What is completed with <Tab> is what Vim expects in that place.  Just try
    it out to see how it works.  In some situations you will not get what you
    want.  That's either because Vim doesn't know what you want, or because
    completion was not implemented for that situation.  In that case you will get
    a <Tab> inserted (displayed as ^I).

    LIST MATCHES

    When there are many matches, you would like to see an overview.  Do this by
    pressing CTRL-D.  For example, pressing CTRL-D after:

    	:set is

    results in:

    	:set is
    	incsearch  isfname    isident    iskeyword  isprint
    	:set is

    Vim lists the matches and then comes back with the text you typed.  You can
    now check the list for the item you wanted.  If it isn't there, you can use
    <BS> to correct the word.  If there are many matches, type a few more
    characters before pressing <Tab> to complete the rest.
       If you have watched carefully, you will have noticed that "incsearch"
    doesn't start with "is".  In this case "is" stands for the short name of
    "incsearch".  (Many options have a short and a long name.)  Vim is clever
    enough to know that you might have wanted to expand the short name of the
    option into the long name.

    THERE IS MORE

    The CTRL-L command completes the word to the longest unambiguous string.  If
    you type ":edit i" and there are files "info.txt" and "info_backup.txt" you
    will get ":edit info".

    The 'wildmode' option can be used to change the way completion works.
    The 'wildmenu' option can be used to get a menu-like list of matches.
    Use the 'suffixes' option to specify files that are less important and appear
    at the end of the list of files.
    The 'wildignore' option specifies files that are not listed at all.

    More about all of this here: |cmdline-completion|

    *20.4*	Command line history

    In chapter 3 we briefly mentioned the history.  The basics are that you can
    use the <Up> key to recall an older command line.  <Down> then takes you back
    to newer commands.

    There are actually five histories.  The ones we will mention here are for ":"
    commands and for "/" and "?" search commands.  The "/" and "?" commands share
    the same history, because they are both search commands.  The three other
    histories are for expressions, debug mode commands and input lines for the
    input() function.  |cmdline-history|

    Suppose you have done a ":set" command, typed ten more colon commands and then
    want to repeat that ":set" command again.  You could press ":" and then ten
    times <Up>.  There is a quicker way:

    	:se<Up>

    Vim will now go back to the previous command that started with "se".  You have
    a good chance that this is the ":set" command you were looking for.  At least
    you should not have to press <Up> very often (unless ":set" commands is all
    you have done).

    The <Up> key will use the text typed so far and compare it with the lines in
    the history.  Only matching lines will be used.
       If you do not find the line you were looking for, use <Down> to go back to
    what you typed and correct that.  Or use CTRL-U to start all over again.

    To see all the lines in the history:

    	:history

    That's the history of ":" commands.  The search history is displayed with this
    command:

    	:history /

    CTRL-P will work like <Up>, except that it doesn't matter what you already
    typed.  Similarly for CTRL-N and <Down>.  CTRL-P stands for previous, CTRL-N
    for next.

    *20.5*	Command line window

    Typing the text in the command line works differently from typing text in
    Insert mode.  It doesn't allow many commands to change the text.  For most
    commands that's OK, but sometimes you have to type a complicated command.
    That's where the command line window is useful.

    Open the command line window with this command:

    	q:

    Vim now opens a (small) window at the bottom.  It contains the command line
    history, and an empty line at the end:

    	+-------------------------------------+
    	|other window			      |
    	|~				      |
    	|file=============================|
    	|:e c				      |
    	|:e config.h.in			      |
    	|:set path=.,/usr/include,,	      |
    	|:set iskeyword=@,48-57,_,192-255     |
    	|:set is			      |
    	|:q				      |
    	|:				      |
    	|command-line=========================|
    	|				      |
    	+-------------------------------------+

    You are now in Normal mode.  You can use the "hjkl" keys to move around.  For
    example, move up with "5k" to the ":e config.h.in" line.  Type "$h" to go to
    the "i" of "in" and type "cwout".  Now you have changed the line to:

    	:e config.h.out

    Now press <Enter> and this command will be executed.  The command line window
    will close.
       The <Enter> command will execute the line under the cursor.  It doesn't
    matter whether Vim is in Insert mode or in Normal mode.
       Changes in the command line window are lost.  They do not result in the
    history to be changed.  Except that the command you execute will be added to
    the end of the history, like with all executed commands.

    The command line window is very useful when you want to have overview of the
    history, lookup a similar command, change it a bit and execute it.  A search
    command can be used to find something.
       In the previous example the "?config" search command could have been used
    to find the previous command that contains "config".  It's a bit strange,
    because you are using a command line to search in the command line window.
    While typing that search command you can't open another command line window,
    there can be only one.

    Next chapter: |usr_21|  Go away and come back

    Copyright: see |manual-copyright|  vim:tw=78:ts=8:noet:ft=help:norl:

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