I pressed ~TabTab on the bash command prompt and got an unexpected set of completions.
First it looked like all the folks in the
/Users directory, and a lot more.
Then I thought it was doing the reverse lookup of folks with "home" directories in
/etc/password, or perhaps the ones that were
/var/empty -- this seems about right.
What I'm curious about is what's really going on and why this works as it does.