How to make the hardware beep sound in Mac OS X 10.6

tput bel works in most shells.

In OS X, this (and any other command that makes the bell go off) also gets you a badge if the command is executed when Terminal was not in the foreground:

Indeed, the following is effective and somewhat melodic:

say -v Bells "dong dong dong"

[Update] Unfortunately Bells is no longer included in latest OS X. Try:

say -v Victoria Do your homework!

Use the following to explore voices:

say -v \?

Printing \a did not always work for me (MBA, 10.7.4). I use this instead:

say "beep"

write echo ^G in the bash. to create the ^G press ctrl+v and then ctrl+g.