How to do case insensitive search in Vim

Question

I'd like to search for an upper case word, for example COPYRIGHT in a file. I tried performing a search like:

/copyright/i    # Doesn't work

but it doesn't work. I know that in Perl, if I give the i flag into a regex it will turn the regex into a case-insensitive regex. It seems that Vim has its own way to indicate a case-insensitive regex.

Answer 1

You need to use the \c escape sequence. So:

/\ccopyright

To do the inverse (case sensitive matching), use \C instead.

Answer 2

As well as the suggestions for \c and ignorecase, I find the smartcase very useful. If you search for something containing uppercase characters, it will do a case sensitive search; if you search for something purely lowercase, it will do a case insensitive search. You can use \c and \C to override this:

:set ignorecase
:set smartcase
/copyright      " Case insensitive
/Copyright      " Case sensitive
/copyright\C    " Case sensitive
/Copyright\c    " Case insensitive

See:

:help /\c
:help /\C
:help 'smartcase'

Answer 3

You can set the ic option in Vim before the search:

:set ic

To go back to case-sensitive searches use:

:set noic

ic is shorthand for ignorecase

Answer 4

You can issue the command

:set ignorecase

and after that your searches will be case-insensitive.

Answer 5

To switch between case sensitive and insensitive search I use this mapping in my .vimrc

nmap <F9> :set ignorecase! ignorecase?

Answer 6

As others suggested:

:set ic

But the cool stuff is You can toggle such modes with:

:set ic!

Answer 7

You can use in your vimrc those commands:

• set ignorecase - All your searches will be case insensitive
• set smartcase - Your search will be case sensitive if it contains an uppercase letter

You need to set ignorecase if you want to use what smartcase provides.

I wrote recently an article about Vim search commands (both built in command and the best plugins to search efficiently).

Answer 8

put this command in your vimrc file

set ic 

always do case insensitive search

Answer 9

The good old vim[grep] command..

:vimgrep /example\c/ &

• \c for case insensitive
• \C for case sensitive
• % is to search in the current buffer

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Answer 10

I prefer to use \c at the end of the search string:

/copyright\c

Answer 11

As @huyz mention sometimes desired behavior is using case-insensitive searches but case-sensitive substitutions. My solution for that:

nnoremap / /\c
nnoremap ? ?\c

With that always when you hit / or ? it will add \c for case-insensitive search.

Answer 12

Vim have 2 modes

1.edit mode

2. normal mode( Esc )

Search will work for normal mode

/\c for case sensitive

/\csearch

Answer 13

You can set ignorecase by default, run this in shell

echo "set ic" >> ~/.vimrc