I've written more shell scripts than I can count, but I still stumble upon tricks that honestly blow my mind far too often than I care to admit. Latest thing that blew my head clean off? The shell colon.

Published 23 July 2026 at 03:53 UTC Modified 26 July 2026 at 05:33 UTC Author Tags #shell

#posix

#unix

In a land far-far away..

... there was once a far too cold cup of coffee next to a freshly brewed far-too-hot one. Four different terminals where three could have been closed an hour ago, and a shell script which I really (really) did not want to write.

Who would have thought a single colon would be the one to save the day night?

Note : Want your mind blown straight away? See more colons in the limelight .

Checking for required arguments

This is a familiar dance, it's pretty much muscle memory by this point.…