book) awk & sed
online) awk one-liners
and
www.awk.info (which I just discovered while looking up a third answer to this post. )
The "awk one-liners" might be among the tons of information at that .info site, too busy to
check today.
And if the "apropos" command is at your workstation, "apropos awk" may give a few man pages to browse; some may have links within them.