1638 - Backslashes

I searched my .bash_history for the line with the highest ratio of special characters to regular alphanumeric characters, and the winner was: cat out.txt | grep -o "[[(].*[])][^)]]*$" ... I have no memory of this and no idea what I was trying to do, but I sure hope it worked.

This is an archival copy of the works from xkcd.com.