Single-line comments begin with a pound sign # and go to the end of the line:

# This is a comment

my $foo = "bar"; # This is also a comment

Multi-line comments start with = and with the =cut statement. These are special comments called POD (Plain Old Documentation).

Any text between the markers will be commented out:

=begin comment

This is another comment.
And it spans multiple lines!

=end comment

=cut