Find filenames with uppercase extension

Question

How can I find all the files with their extension in uppercase in recursively in a directory.

I've tried :

$ find -name "*.[A-Z][A-Z][A-Z]"

Seems to work but of course this does not check files with more than 3 letters after the last dot.

Answer 1

The following works for simple cases:

find -name "*.*[A-Z]*" ! -name "*.*[^A-Z]*"

It is liable to fail for files with two or more dots in the name. For this case you need to use Regular Expressions, eg with grep:

find | grep '\.[A-Z][A-Z]*$'

or egrep:

find | egrep '\.[A-Z]+$'

Following Kamil Maciorowski's comment, the answer could be made locale-independent by using [:upper:] in place of A-Z, as in:

find | egrep '\.[[:upper:]]+$'

I'm afraid that we native-English speakers can easily forget such matters.

Answer 2

You can use RE with -regex option

find -regextype posix-egrep -regex '.*\.[A-Z]{3}'

There are some points using RE with find, I learned that in a pt_BR book.

-regex option wants to match the whole path, so the .* matches everything before the actual RE you want to match. If the RE can be in the middle, another .* must be place at the end.

The -regextype tells which meta-characters must be escaped or not.

What I know is that in Unix/BSD find -E allows all meta-characters unescaped, and in GNU/Linux the same is -regextype posix-extended, -regextype posix-awk or -regextype posix-egrep.