I am the senior system administrator for a national ISP. We run a cluster of blade servers as our primary mail/Web/DNS/RADIUS farm. I have found several tools that I cannot live without in this environment.
Pipefitting commands is integral to my daily routine. It's not uncommon for me to have a command with 10 or more pipes in it. The | operator makes everything more useful, but a few of the commands I use religiously with it are cut, grep, perl -ne (more on that in a second), find, wc, xargs, nc (netcat), sort, head, tail, and uniq.
If the Internet is the Information Superhighway, then Perl is the Fix-a-Flat and the spare tire -- and the spare drive-shaft, should you need it. Anything you can do in a shell or sed or awk script, you can do in Perl. With the -ne options, you can iterate automatically over every line of input in a pipe chain:
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