"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