Isaac pointed out the
tac linux utility to me today. It's probably my new favorite Linux command. It's just like
cat, except it outputs your text files in reverse order. Great for grepping and looking for the last X lines in a log file. Saves a lot of time of grepping through big files.
tac /var/log/maillog | grep email@example.com | head -n 10
We also found out that in the above example the tac (or cat if you use that) quits after the head achieves its goal. Thus if you output a large file and filter it with
head it will stop parsing the file when head quits (gets 10 lines). Pretty smart.