Qmail

Some people can't understand why I prefer qmail to other mailers.

The simplest reason is that its safe and easy to apply changes to. Each of the processes can have a small wrapper applied to them for example.

readproctitle

Sometimes something bad happens and you get a lot of errors recorded in readproctitle's output in ps. To clear this, I've found the following bit of perl solves this:

perl -e 'print "." x 512;' > /proc/$(pgrep readproctitle)/fd/0

You may find better ways, but this does the job for me.