Debugging
Using print( ) functions in “if” blocks
Testing small pieces of code
Warnings
Either:
use warnings; # this is a "pragma," and is placed at the top of a script, below the shebang
or:
#!/usr/bin/perl -w # use the -w flag directly in the shebang
or:
perl -w myscript.pl
Diagnostics: Full Documentation
Either:
use diagnostics;
or:
perl -w myscript.pl