You might also want to learn about the -p and -i command line flags. They are also very useful.

A few easy things you could try:

- Removing DOS carriage returns from a file under Unix (a sort of dos2unix utility)

- Renaming in uppercase (or lowercase) all the files of a directory, checking first that the uppercase (or lowercase) version does not already exists.

- Removing all comments from a Perl program

- Crypting a file or a string in rot13 (each letter shifted by 13 positions in the alphabet), and decrypting it.

- Listing all the modules installed in your Perl environment

- Listing all the files in a directory, sorted by name / size / age or whatever other property you might want.

- Changing the date format in a text file (for example from MM DD, YYYY to YYYY-MM-DD or vice-versa.

- Printing the multiplication tables for numbers between 1 and 10.