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.

score 2573 · Accepted Answer · edited May 15 '20 at 01:27

2573

You can use the \c escape sequence anywhere in the pattern. For example:

/\ccopyright or /copyright\c or even /copyri\cght

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

edited May 15 '20 at 01:27

lurker

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answered Feb 18 '10 at 09:18

Chinmay Kanchi

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Also, `\c` can appear anywhere in the pattern, so if you type a pattern and then decide you wanted a case-insensitive search, just add a `\c` at the end. – Alok Singhal Feb 18 '10 at 09:20
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I like to add `set ignorecase` for case-insensitive searching in my vimrc, and I can use `\C` to do a case-sensitive search similar to what @AlokSinghal mentioned. – Nick McCurdy Aug 05 '13 at 18:23
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There's also `set smartcase` which will automatically switch to a case-sensitive search if you use any capital letters. – Zaz Jun 05 '15 at 22:22
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Just want to add to Zaz's comment. `set smartcase` applies only when `set ignorecase` is already active. I was stumped on this for a while. See [Vim Tips](http://vim.wikia.com/wiki/Searching#Case_sensitivity). – Tan Wang Jul 08 '16 at 20:58
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Whut? Answer says: "Use `\c`. For the inverse, use `\c`." I think the "for the inverse" answer should state that a search for `/copyright` is case sensitive by default. – coderMe Oct 28 '16 at 02:45
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@coderMe, It's the capitalization, `\c` versus `\C` – Aaron McDaid Oct 28 '16 at 13:25
The comments in Zaz and VimTips should be incorporated in this answer. Or should reference the other answer by Matthieu as it doesn't make much sense without it. – Adrian Jan 15 '18 at 22:59

DrAl · Answer 2 · 2016-11-29T09:24:42.793

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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'

edited Nov 29 '16 at 09:24

answered Feb 18 '10 at 12:11

DrAl

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The problem with `ignorecase` is that it affects substitutions as well as searches. I find that it makes sense to have (smart) case-insensitive searches but case-sensitive substitutions by default. But there's no way to do that that I know. – huyz Jul 02 '11 at 14:18
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Worth noting that for `smartcase` to work, you also need `set ignorecase`. Great tip though, thanks! – Skilldrick Mar 28 '12 at 18:59
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I believe you could just use a \C in your search expression for substitutions, like this: `:%s/lowercasesearch\C/replaceString/g`. This doesn't create the default functionality you desire, but it does allow you to force case-sensitivity for replacements while still benefiting from smartcase when searching. – Anthony DiSanti Oct 15 '12 at 23:44
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You can also set the [`I` flag](http://vimdoc.sourceforge.net/htmldoc/change.html#:s_flags) on a substitution to force the pattern to be case-sensitive. Like `:%s/lowercasesearch/replaceString/gI`. – Rory O'Kane Aug 21 '13 at 22:19
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Note from the help page (useful if you are "*" addicted like me): `After "*" and "#" you can make 'smartcase' used by doing a "/" command, recalling the search pattern from history and hitting . ` – mcella Nov 06 '14 at 17:21
should add @Skilldrick 's comment to the answer in my opinion – Dane Mar 02 '18 at 05:18

score 352 · Answer 3 · answered Feb 18 '10 at 09:18

352

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

answered Feb 18 '10 at 09:18

Nathan Fellman

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also your only option if you're unlucky enough to still use Vi instead of Vim. `\c` doesn't work in vi. – bluppfisk Dec 12 '19 at 13:09

score 72 · Answer 4 · answered Feb 18 '10 at 09:19

72

You can issue the command

:set ignorecase

and after that your searches will be case-insensitive.

answered Feb 18 '10 at 09:19

Paolo Tedesco

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Matthieu · Answer 5 · 2018-08-19T15:42:49.077

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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).

edited Aug 19 '18 at 15:42

answered Dec 26 '17 at 08:36

Matthieu

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It seems that `set smartcase` does not perform case insensitive searches if I do not use uppercase letters...is that normal? – caneta Feb 21 '18 at 11:18
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Ok, just read below that you have to both set ignorecase and smartcase to have it work. Sorry about that! – caneta Feb 21 '18 at 11:21

score 51 · Answer 6 · answered Feb 23 '10 at 11:51

51

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

nmap <F9> :set ignorecase! ignorecase?

answered Feb 23 '10 at 11:51

vbd

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Yes, but `ignorecase?` shows you the current state of the flag. (in the command line) – Boris Brodski Jan 22 '16 at 22:10
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Thank you! To me, this is the most useful answer on the page: a way to quickly toggle between the two modes depending on what you're searching for at that exact moment. – Ben Hillier May 01 '19 at 08:28
Yes, it's better to have `ignorecase?` so you know the current state. – COil Feb 18 '23 at 16:35
BTW, it's better to add `` at the end, so the command is validated, and you don't have to hit the enter key (at least with neovim). – COil Feb 18 '23 at 16:42

score 27 · Answer 7 · answered Nov 18 '17 at 01:18

27

The good old `vim[grep]` command..

:vimgrep /example\c/ &

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

answered Nov 18 '17 at 01:18

Mick

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`Cannot open file "&"` – Vitaly Zdanevich Jun 13 '18 at 07:41
I guess he they meant `%` instead of `%`. – oarfish Apr 22 '20 at 10:20

score 27 · Answer 8 · answered Dec 01 '20 at 17:02

27

By default, all searches in vi are case-sensitive. To do a case-insensitive search, go into command mode (press Escape), and type-
:set ignorecase
You can also type - :set ic as an abbreviation.

To change back to case-sensitive mode, type-
:set noignorecase or :set noic in command mode

answered Dec 01 '20 at 17:02

Yogesh Jilhawar

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`:set ic!` will toggle – robmsmt Feb 08 '21 at 18:38

Thomas · Answer 9 · 2018-08-13T11:10:06.187

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As others suggested:

:set ic

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

:set ic!

edited Aug 13 '18 at 11:10

answered Jan 19 '17 at 09:34

Thomas

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score 21 · Answer 10 · answered Jun 15 '17 at 01:54

21

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

/copyright\c

answered Jun 15 '17 at 01:54

Nick Tsai

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score 19 · Answer 11 · edited Nov 24 '15 at 15:02

19

put this command in your vimrc file

set ic

always do case insensitive search

edited Nov 24 '15 at 15:02

Community

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answered May 19 '15 at 10:31

WALID BELRHALMIA

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I don't know why but my vim is set to case-insensitive by default, to counter this. use `set noic`. – user1510539 Mar 22 '16 at 13:22

score 10 · Answer 12 · answered Feb 12 '16 at 09:58

10

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.

answered Feb 12 '16 at 09:58

pbogut

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Not a bad suggestion, but does it prevent you from using the `smartcase` option? – Trebor Rude Feb 26 '16 at 23:53
Looks like it would since \c overrides `smartcase` – Matthew Woo Jan 10 '17 at 01:57

score 5 · Answer 13 · answered Mar 13 '17 at 05:38

5

Vim have 2 modes

1.edit mode

normal mode( Esc )

Search will work for normal mode

/\c for case sensitive

/\csearch

answered Mar 13 '17 at 05:38

Gowthaman D

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What about visual mode? – user202729 Jun 27 '18 at 04:18

score 3 · Answer 14 · answered Jul 04 '17 at 01:40

3

You can set ignorecase by default, run this in shell

echo "set ic" >> ~/.vimrc

answered Jul 04 '17 at 01:40

Steely Wing

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DevWL · Answer 15 · 2021-09-03T21:03:19.303

Note it is a difference where you place modifiers such as "\c" in your expresion:

You can use the \c escape sequence anywhere in the pattern

Regardless from the accepted answers, which states that it is no difference of where to place modyfier in a regex pattern, its looks like it actually does matter.

example text:

asdasdasdasdasd wiktor asdasdasdasd   
adasdasdasd wiktor asdasda ahjkjlkhjkl
asdasd asd asdasdasdasd iuuuu -       
asdjkkkkkkkaopbsdasda                 
wiktor ----(---------------------)--

Match

\c^.*A?.*$
^\c.*A?.*$
^.*\cA?.*$
^.*A\c?.*$

will output:

No match

^.\c*A?.*$
^.*A?\c.*$
^.*A?.\c*$
^.*A?.*$\c

will output:

vim -version VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Jun 1 2020 06:42:35) Included patches: 1-869

score -2 · Answer 16 · answered Aug 02 '20 at 15:15

Some important information, if u want to find out more about the commands of vim, as mentioned below u can give a try the following steps :

invoke the command "help" follow by a space and then complete the word with TAB key, once u find the right command press return key.

:help ignorecase

information like the following will be displayed :

you will be able to move forward and backward and also watch the short command, such as the case of "ignorecase" ( 'ic' ). In addition, another short example could be the case of 'smartcase' ('scs' and some more) :

In order to leave of the documentation just type ":q" as usual and you will return to "command mode" .

:q

I really hope the information provided would be helpful for someone.

Best regards,

How to do case insensitive search in Vim

16 Answers16

The good old `vim[grep]` command..

Note it is a difference where you place modifiers such as "\c" in your expresion:

Match

No match

Linked

Related

How to do case insensitive search in Vim

16 Answers16

The good old vim[grep] command..

Note it is a difference where you place modifiers such as "\c" in your expresion:

Match

No match

Linked

Related

The good old `vim[grep]` command..