Have you ever typed out a really long command, realized it worked great, and then wanted to save it to a file? There’s an easy bash trick you can use to do just that.
echo “!!” > filename
I sometimes use this trick when I’m building a script, but I’m not sure exactly what commands I want… so I type them out on the shell to make sure they execute properly, and then use the same command but with >> to append them to the end of the script I’m working on, like this:
echo “!!” >> scriptname.sh
If you execute another command after the last one, you can save that one like this:
echo “!-2” >> scriptname.sh
Very useful, or at least fun to learn.