Vim: Dynamic Case Insensitive/Sensitive Search

nabbisen - Mar 20 '19 - - Dev Community

Hi 🙂
This post is about a small tip to search words in Vim / Neovim.

I sometimes wanted to ignore case after beginning to search some words; It was not applied under the default settings, noignorecase and nosmartcase (at least, in the OpenBSD 6.4's package).

It was difficult for me to customize a config file, aka ~/.vimrc / ~/.config/nvim/init.vim then.
Moreover, I didn't like stopping the search to type :set ignorecase which may have to be reset afterwards every time I meet the case.
Additionally, my life would have been harder if I had been accustomed to restart the program with reading a custom config file with -u option as needed: vim -u %config-file% / nvim -u %config-file%.

I found the way after all:
\c / \C are the magic words 😊

\c enables case insensitive search dynamically:

/\c%keyword(s)%
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\C is the opposite, i.e. sensitive search:

/\C%keyword(s)%
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Remember these options are prior to the config settings.

image

For example, under noignorecase and nosmartcase environment:

(Keyword) "coffeebreak" is "CoffeeBreak" is "COFFEEBREAK" is
coffeebreak hit not hit * not hit *
CoffeeBreak not hit hit not hit
\ccoffeebreak hit hit hit
\cCoffeeBreak hit hit hit
\Ccoffeebreak hit not hit not hit
\CCoffeeBreak not hit hit not hit

* Under ignorecase and smartcase, it's hit. (Thus, the combination of the settings may be useful when a custom config file is available.)

If you want to read about these options in the official document, type in Vim:

:help ignorecase
:help smartcase
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The gate is open!

Thank you for your reading 😄
I wish your happy life with Vim.

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