What is your single most favorite command-line trick using Bash? [closed]

Answer 1

I like to construct commands with echo and pipe them to the shell:

$ find dir -name \*~ | xargs echo rm
...
$ find dir -name \*~ | xargs echo rm | ksh -s

Why? Because it allows me to look at what's going to be done before I do it. That way if I have a horrible error (like removing my home directory), I can catch it before it happens. Obviously, this is most important for destructive or irrevocable actions.