see below sudo code:
for file in wallet_files:
pywallet.py --wallet=file --[any other options]
Or you can import the relevant functions and/or create a class that inherets the relevant classes, and create a loop that reads each file you have.
It's very easy to convert this to Bash - in the place of wallet_files, just put the name of each wallet file separated by space:
for file in a.dat b.dat c.dat; do
pywallet.py --wallet=$file --[any other options]
done
This can be pasted as-is on the terminal. No need to go out and make a big script for it, it can be accomplished in just 4 lines