LCA2013 shirtgate was an incident at linux.conf.au 2013 on February 1 2013 where an attendee wore a t-shirt with writing on the back reading: who | grep -i blonde | date && (cd $HOME; unzip; touch; strip; finger; mount; yes; umount; make clean); sleep These are all standard UNIX commands, and are syntactically but not semantically valid as used on the shirt. The semantics are instead sexual (search available users for a blonde, etc).