SHAC: i just remembered one of the silliest sysadmin hacks ever
SHAC: if you have a file that sometimes has duplicate lines
SHAC: and sometimes doesnt
SHAC: and you want to process each line once
SHAC: if file is called foo
cat foo foo | sort | uniq -d > bar
SHAC: so you cat foo twice into sort so EVERY line has at least 2 instances… then you sort them all out… then you use uniq and say “tell me what lines are duplicated”
SHAC: of course every line is duplicated, but uniq only tells you that once
BRAIN: that is brilliant
SHAC: “boss” taught me it like 4 years ago