Photoshop mangles file names when you run batch saves on them, so I’ve had to rename a bunch of files after processing. Here’s what I do from the shell prompt to rename a bunch of files in a PictsFolder.
Create a file called rename.sh
#!/bin/bash
cd /Users/gmiller/Desktop/PictsFolder
mv 1.png a.png
mv 2.png b.png
exit
chmod it to be executable. I use chmod 777 rename.sh because I’m lazy. Then run it from the command line.
jscarry$ /Users/gmiller/Files/renamePicts.sh
Be sure to escape special characters like spaces in your file names.
e.g. File\ Name\ With\ Spaces.png