rename a file to its md5 (with its extension)

rename.sh

#!/bin/bash

if [ $# != 1 ]; then
  echo 'usage: % <file>'
  exit 0
fi

MD5=md5
which md5sum > /dev/null && MD5=md5sum

TARGET=$1
EXT=${TARGET##*.}

which md5sum > /dev/null
if [ $? = 0 ]; then
  HASH=`md5sum $TARGET | cut -d ' ' -f1`
else
  HASH=`md5 $TARGET |awk '{print $NF}'`
fi

if [ $EXT = $TARGET ]; then # no extension?
  echo mv $TARGET ${HASH}
  mv $TARGET ${HASH}
else
  echo mv $TARGET ${HASH}.${EXT}
  mv $TARGET ${HASH}.${EXT}
fi

% wget -O ~/bin/ren https://gist.githubusercontent.com/cympfh/e3a861bbbb0d0002e6a7/raw/d6bdd35250ecb0490a8b4e4a4555495f8f47a54f/rename.sh && chmod +x ~/bin/ren
% ren CIExbBuUcAEsTIW.jpg:large.jpeg
mv CIExbBuUcAEsTIW.jpg:large.jpeg 0d64e244497219e306f2d6dacbde1bf6.jpeg