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

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 this from a shell?

From stackoverflow

• Try this (not sure if it's the best way, but it works):

  find . -type f | perl -ne 'print $1 if m/\.([^.\/]+)$/' | sort -u
  

  It work as following:

  • Find all files from current folder
  • Prints extension of files if any
  • Make a unique sorted list

• Reursive version:

  find . -type f | sed -e 's/.*\.//' | sed -e 's/.*\///' | sort -u
  

  If you want totals (how may times the extension was seen):

  find . -type f | sed -e 's/.*\.//' | sed -e 's/.*\///' | sort | uniq -c | sort -rn
  

  Non-recursive (single folder):

  for f in *.*; do printf "%s\n" "${f##*.}"; done | sort -u
  

  I've based this upon this forum post, credit should go there.

  : you are going to execute bash for each file name you find??

  ChristopheD : Good point, changed the solution...

• 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
  

  SiegeX : No need for the pipe to 'sort', awk can do it all: find . -type f -name "*.*" | awk -F. '!a[$NF]++{print $NF}'

  : And it's output is also uniq! Nice!

• 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)"
  

• 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
  

• Powershell: dir -recurse | select-object extension -unique

  thanks to http://kevin-berridge.blogspot.com/2007/11/windows-powershell.html

  GloryFish : Hey that's pretty cool, and very readable.

  Kevin Berridge : Thanks for linking to my blog!