Delete all files except a few using bash command

I have a directory containing lot of files in different formats. I would like to know how I can delete all files with specific format (Lets say *.dat) except a few files in a same format (e.g. A.dat and B.dat). Please advise!

Answer

I’d write a little script (as a command-line one-liner it is slightly too big):

#!/bin/sh
for f in *.dat; do
   case $f in
      (A.dat|B.dat)
         ;;           # do nothing
      (*)
         rm -- "$f";; # remove the file
   esac
done

As an alternative, you could use an interactive rm -i *.dat which asks you for each file if it should be removed. Answer y for the files you no longer need, and n for A.dat and B.dat.

Modern shells like zsh and bash also offer powerful globbing features for your problem. I suggest you read their manual pages, which will help you become a proficient shell guru.