How can I find all of the distinct file extensions in a folder hierarchy?

Question

On a Linux machine I would like to traverse a folder hierarchy and get a list of all of the distinct file extensions within it.

What would be the best way to achieve

Answer 1

No need for the pipe to sort, awk can do it all:

find . -type f | awk -F. '!a[$NF]++{print $NF}'

Answer 2

My awk-less, sed-less, Perl-less, Python-less POSIX-compliant alternative:

find . -type f | rev | cut -d. -f1 | rev  | tr '[:upper:]' '[:lower:]' | sort | uniq --count | sort -rn

The trick is that it reverses the line and cuts the extension at the beginning.
It also converts the extensions to lower case.

Example output:

   3689 jpg
   1036 png
    610 mp4
     90 webm
     90 mkv
     57 mov
     12 avi
     10 txt
      3 zip
      2 ogv
      1 xcf
      1 trashinfo
      1 sh
      1 m4v
      1 jpeg
      1 ini
      1 gqv
      1 gcs
      1 dv

Answer 3

Find everythin with a dot and show only the suffix.

find . -type f -name "*.*" | awk -F. '{print $NF}' | sort -u

if you know all suffix have 3 characters then

find . -type f -name "*.???" | awk -F. '{print $NF}' | sort -u

or with sed shows all suffixes with one to four characters. Change {1,4} to the range of characters you are expecting in the suffix.

find . -type f | sed -n 's/.*\.\(.\{1,4\}\)$/\1/p'| sort -u

Answer 4

Since there's already another solution which uses Perl:

If you have Python installed you could also do (from the shell):

python -c "import os;e=set();[[e.add(os.path.splitext(f)[-1]) for f in fn]for _,_,fn in os.walk('/home')];print '\n'.join(e)"

Answer 5

None of the replies so far deal with filenames with newlines properly (except for ChristopheD's, which just came in as I was typing this). The following is not a shell one-liner, but works, and is reasonably fast.

import os, sys

def names(roots):
    for root in roots:
        for a, b, basenames in os.walk(root):
            for basename in basenames:
                yield basename

sufs = set(os.path.splitext(x)[1] for x in names(sys.argv[1:]))
for suf in sufs:
    if suf:
        print suf

Answer 6

I don't think this one was mentioned yet:

find . -type f -exec sh -c 'echo "${0##*.}"' {} \; | sort | uniq -c