bash find using regex is not case sensitive

问题

I need to find files starting with three lowercase letters but for some reason I'm getting an undesired case-insensitive behavior. I'm using find with the -regex option but it finds even the files starting with capital.

$ find . -regextype posix-egrep -regex '.*/[a-z]{3}\w+\.abc'
./TTTxxx.abc
./tttyyy.abc

prints the same as:

$ find . -regextype posix-egrep -regex '.*/[A-Z]{3}\w+\.abc'
./TTTxxx.abc
./tttyyy.abc

If instead of using a range of characters I use a single character, works as sensitive, printing only the lowercase file.

find . -regextype posix-egrep -regex '.*/[t]{3}\w+\.abc'
./tttyyy.abc

I've tried using different regextypes and the result is the same.

In addition, an egrep to seems to work:

find . -regextype posix-egrep -regex '.*/.+\.abc' |  egrep '/[a-z]\w+\.abc'
./tttyyy.abc

Why is the "find -regex" case-insensitive when using a char range ?

Note: I need to use find as I need the -exec option.

Many thanks.

回答1:

Accroding to Why does [A-Z] match lowercase letters in bash?, the collation is the issue here:

Standard collations with locales such as en_US have the following order:

aAbBcC...xXyYzZ

Between a and z (in [a-z]) are ALL uppercase letters, except for Z. Between A and Z (in [A-Z]) are ALL lowercase letters, except for a.

So you need to list explicitly all lowercase letters or change the collation: $ export LC_COLLATE=C and use standard [a-z].

[...]{3}\w\.abc - this pattern, where [...] is [a-z] or lowercase letters listed, will get you filenames.

来源：https://stackoverflow.com/questions/51727109/bash-find-using-regex-is-not-case-sensitive