countmail

The countmail program counts your mail and tells you about it rather obnoxiously.

from(1)

The countmail program first appeared in NetBSD 1.3.

countmail was first written by Noah Friedman <friedman@splode.com> in 1993. This version was written by Charles M. Hannum ⟨mycroft@NetBSD.org⟩.

The read loop is horrendously slow on every shell implementation tried. countmail uses from(1) and wc(1) instead, though these are not shell builtins.