Handy UNIX tips
From b0rken.org
Sort two input files to diff (bash):
$ diff <(sort file1) <(sort file2)
Calculate numerical difference between a field in the current line of output and the previous line, in this case field 2. Useful for determining traffic rates from netstat byte counters, for example.
| awk '/obytes/ { if (NR > 1) { print $2 - prev }; prev = $2; }'
Print a list with a pause between every 10 lines...
| perl -pe 'sleep 5 unless $x++%10;$|=1'
...and execute a command for every 10 lines of input
| xargs -L 10 command
