in reply to Favourite One-liners?

I always use:
perl -e 'print <>' filename
That's a one-liner I would never use. It's inefficient, and a lot longer to type than cat filename.

I use one-liners a lot. However, I seldomly use Perl in one-liners - when it comes to one-liners a Unix shell (with the standard Unix tools) usually beats Perl.