find specific file extension with find command

Question

I would like to find any files within a given root that contain arbitrary extensions in the filename. I saw this post: How to delete all files with certain suffix before file extension

Based on that information, I tried this:

find . -iregex ".*\.\(wav\|aif\|wave\|aiff\)"

This seems like it should work, but I don't get any results printed to the terminal window.

Can anyone offer advice? I'm on OSX 10.7

Thanks, jml

Answer 1

You are looking for:

find . -regex ".*\.\(wav\|aif\|wave\|aiff\)"

You were missing escape, \, characters on the or, |, operators

Answer 2

Is that an emacs style regex?

If not, try using -regextype. From the find man page on Linux (archaic):

• -regextype type

  Changes the regular expression syntax understood by -regex and -iregex tests which occur later on the command line. Currently-implemented types are emacs (this is the default), posix-awk, posix-basic, posix-egrep and posix-extended.

---

On MacOS X, the manual page for find says:

-iregex pattern

Like -regex, but the match is case insensitive.

-regex pattern

True if the whole path of the file matches pattern using regular expression. To match a file named './foo/xyzzy', you can use the regular expression '.*/[xyz]*' or '.*/foo/.*', but not 'xyzzy' or '/foo/'.

Some experimentation shows that:

find pdf -iregex ".*/.*.pdf"

finds a whole lot of PDF files in my folder full of them, but none of these variants find anything:

find pdf -iregex ".*/.*\.(pdf|doc|docx)"
find pdf -iregex ".*/.*\.\(pdf|doc|docx\)"
find pdf -iregex ".*/.*.(pdf|doc|docx)"
find pdf -iregex ".*/.*.\(pdf|doc|docx\)"

Consequently, one is forced to assume that the regexes supported by MacOS X (BSD) find do not include alternation (parentheses and pipes) amongst the recognized characters. 'Tis a pity: man 7 re_format implies it might, but it doesn't. The -regextype option is not supported on MacOS X (BSD), it seems.

So, it may be simplest to install GNU find, or to do N separate searches for the N different file extensions, or do one search for files in general and use egrep '\.(aff|wave?|aiff)$' to catch the files you're interested in. That rather assumes you don't use newlines in file names (spaces etc are OK, but newlines are not).