Yup, looks like most shells use that phrase. Hell, what else would
they use???
> foreach file ( `cat /etc/shells` )
if (-f $file) echo -- $file --
if (-f $file) strings $file | grep '[Yy]ou.*have.*mail'
end
-- /bin/sh --
You have mail in $_
You have new mail in $_
-- /bin/bash --
You have mail in $_
You have new mail in $_
-- /bin/csh --
You have %smail.
-- /bin/tcsh --
You have %d mail messages.
You have %d mail messages in %s.
You have %smail.
You have %smail in %s.
-- /bin/ksh --
you have mail in $_
-- /usr/bin/ksh --
you have mail in $_
-- /bin/ash --
you have mail
-- /bin/bsh --
you have mail
-- /bin/zsh --
You have new mail.