I am looking for file "WSFY321.c" in a huge directory hierarchy.
Usually I would use GNU find: find . -name "WSFY321.c"
But I do not know the case, it could be uppercase, lowercase, or a mix of both.

What is the easiest way to find this file?
Is there something better than find . | grep -i "WSFY321.c" ?

3 Answers 3


Recent versions of GNU find have an -iname flag, for case-insensitive name searches.

find . -iname "WSFY321.c"
  • 8
    Also, since you're specifically looking for a file you can probably shave another couple of ticks off that with the -type f flag so it won't bother looking at the name if the inode is a directory. But that's pedantic levels of optimization... Commented Feb 20, 2012 at 9:47
  • For working with some regex you can do find . -iname \*WSFY321.c\* -type f
    – Benj
    Commented Jun 11, 2016 at 22:01
  • 2
    This pattern of adding -i before an option follows for other find options too. Ex: -name to search for a name, and -iname to make it case-insensitive. -path to search for a path, and -ipath to make it case-insensitive. I mention using -ipath in my answer here: Stack Overflow: How to exclude a directory in find . command. Commented Nov 3, 2021 at 19:40

With GNU find, or other versions of find that have it:

find . -iname 'WSFY321.c'

With other versions:

find . -name '[Ww][Ss][Ff][Yy]321.[Cc]'

Or a compromise that's slower but easier to type:

find . -name '????321.c' | grep -i '/WSFY[^/]*$'

Or in zsh:

print -rl -- **/(#i)WSFY321.c
  • @Gilles The grep version is filtering only upper case, and I don't understand the '[^/]' ..(not /)
    – Peter.O
    Commented Feb 20, 2012 at 6:22
  • @Gilles What is the argument to use the single quotes in the first case (exact filename) over no quotes at all?
    – Bernhard
    Commented Feb 20, 2012 at 7:14
  • @Peter.O No * after the / in the bash version. I meant grep -i. I use [^/]* rather than .* so as not to catch files in directories whose name begins with WSFY. Commented Feb 20, 2012 at 10:08
  • 6
    @Bernhard Consistency. Commented Feb 20, 2012 at 10:08
  • Thanks Gilles: I deleted the previous comment with incorrect syntax, and tested the ammended version, but it doesn't work without the * (for an unexpected reason; to me at least).  The case-insensitive option no longer works: shopt -s extglob nocaseglob globstar; printf '%s\n' **/WSFY321.c ... I suppose that's why it is called a nocase‍​ glob: it only works in the context of a glob (or so it seems).
    – Peter.O
    Commented Feb 20, 2012 at 11:34

Two solutions for macOS:

Using GNU find:

brew install findutils --with-default-names
# restart Terminal
find . -iname 'WSFY321.c'

Using GNU sed:

brew install gnu-sed --default-names
# restart Terminal
find -name "$(sed 's|\([[:alpha:]]\)|[\U\1\L\1]|g' <<<'WSFY321.c')"
  • 2
    On macOS Sierra the -iname option is available by default.
    – ThomasW
    Commented May 25, 2017 at 1:13

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