So I was writing this script that logged certain things to a file using a regular redirect. My script was running various commands that outputted a random amount of lines, all in random formats. I wanted to have a timestamp prefixing all of that, similar to what you get in logs written by syslog. I searched around a bit, and ended with this:
ls -l / | awk '{now=strftime("%Y-%m-%d %T %Z"); print now" "$0}'Of course if you want a different timestamp, you just change the arguments you pass to strftime. Quite handy!