me@myaixbox:/home/me/sandbox
$ at -f 1.pl
at: 0481-110 Command usage error; a parameter is missing.
me@myaixbox:/home/me/sandbox
$ uname
AIX

##</code><code>##

me@mylinuxbox:~/sandbox
$ at -f 1.pl
Garbled time
me@mylinuxbox:~/sandbox
$ uname
Linux

##</code><code>##

userid@somebox:/tmp/tmp.66
# at -f 1.pl
bad time specification
userid@somebox:/tmp/tmp.66
# uname
HP-UX