mv all files in a directory with a particular extension -- remove dashes, underscores, spaces, dots (add more if you like) and lowercase the filename

anandroidfilenameconventionconverter.sh

#!/bin/bash

ext=.png

for file in *$ext; do
  baseName=${file%$ext}
  baseNoDashes=$(echo $baseName | tr -d '_- .')
  baseLower=$(echo $baseNoDashes | tr '[:upper:]' '[:lower:]')
  fileNew=$baseLower$ext
  echo Renaming $file to $fileNew
  #mv $file $fileNew #uncomment to actually do it
done

Very cool! Some notes:

The beginning of the for loop is safer as:

for file in "*$ext"

In bash, whenever you are doing substitution or interpolation, it should be done inside of double-quotes. There are some weird rules around expansion and parsing that can catch you off-guard. It is not always a sane system.

So the same would be true everywhere you're using the $() construct to run a command and get its output back. Also for the fileNew declaration.

Another note in case you're not aware - variables in bash are global by default. If you want lexical scoping in the for loop you have to use the local directive when declaring variables.

Other than that it looks good!

PS. One trick I like to avoid having a line in the script that you comment or uncomment is to add a --really-do-it flag to the script. I.e. when you run the script, you'll get to the mv statement where you have an if statement that checks if the --really-do-it flag was set. If it was set, actually do the mv, otherwise say echo "Not actually moving since you didn't specify --really-do-it".

thanks!!