It also occurs to me that people using shells without last-command
   recall (like most NetBSD systems running single-user, I suspect) can be
   quite ticked off at having to retype the filesystem name, especially if
   it's long (which, granted, is unlikely to be the case).

um...

sh(1) has command history built in to it.  `set -o emacs' gives
you emacs-style history commands, and i assume `set -o vi' gives
you vi-style history commands (i have never used this -- i like
vi for editing *files*).

.mrg.

(ps, i agree with cgd, for the record  :-)