Delete everything except a few extensions

Question

Can I modify the rm command with regular expression or something to delete every file in current directory except files with extensions *.bmp, *.wav and *.png? It should be case insensitive because there are files like *.BMP or *.bMP.

thank you

Answer 1

@ChrisDown has given a solution that take into account the difference of files and directories, and also if there is no file to remove.

Given that rm would fail however in these situations, the command could be simplified as

shopt -s extglob nocaseglob
rm !(*.bmp|*.wav|*.png)

Remember to reset the two shell options to their default values. In my case extglob is already set on interactive shells, so I only need

shopt -u nocaseglob

If you would to see in advance what files will be removed, simply substitute the rm with echo.

Answer 2

If you are using bash, you can use a combination of extglob and nocaseglob.

shopt -s extglob nocaseglob
for file in !(@(*.bmp|*.wav|*.png)); do
    [[ -f "${file}" ]] && files+=( "${file}" )
done
(( ${#files[@]} )) && rm "${files[@]}"

Otherwise you can us something like the following:

find . -maxdepth 1 -type f ! \( -iname '*.bmp' -o -iname '*.wav' -o \
    -iname '*.png' \) -delete

Answer 3

I would suggest that you take a little time and do this in multiple steps so you do not do anything accidently silly.

1. create a command to identify the files you want to delete, e.g.

       ls | grep -v *.bmp | grep -v *.wav  # current directory
   

   or

       find . -type f | grep -v *.bmp      # current and sub directories
   

   if the list of returned files is what you want to remove, then

2. recall the last command and add the xargs rm command to it, e.g.

       ls | grep -v *.bmp | grep -v *.wav | xargs rm