# line containing 'cake' but not 'at' # same as: grep 'cake' table.txt | grep -v 'at' # with PCRE: grep -P '^(?!.*at).*cake' table.txt $ awk '/cake/ && !/at/' table.txt blue cake mug shirt -7

sed appears to be able to do this much more efficiently if a large number of files are involved. awk may be easier to remember, but sed seems to be worth a sticky note in my brain.

awk is my weapon of choice when it comes to text processing. Besides, it's syntax is close to C

$(awk -F= '/^Exec/||/^TryExec/ {print $2;exit}' /usr/share/applications/firefox.desktop)

To get all the processes spawned by a process the whole tree needs to be built. I used awk for that. At first it builds a hash array to contain all PID => ,child,child... . At the end it calls a recursive function to extract all the child processes of a given process. The result is passed to another ps to format the result.

print every nth line into a row