Yes, shell scripts can be created with your favorite text editor. TextEdit would work fine, saving as Plain Text instead of Rich Text. You'd need to make the script executable and might want to change its extension from .txt (e.g. to .sh).
A simple shell script could use
osascript to run your AppleScript.
Or, if your AppleScript is a compiled executable command then SD!'s "Run shell script after copy completes" option should be able to run it.
I'm intentionally terse with details here but plenty can be found with a bit of searching.