me@mybox:/home/me/sandbox
$ cat 1.pl
#!/usr/bin/perl
system('echo bob >/tmp/blarney.out');
me@mybox:/home/me/sandbox
$ ./1.pl
me@mybox:/home/me/sandbox
$ cat /tmp/blarney.out
bob
me@mybox:/home/me/sandbox
$ rm /tmp/blarney.out
me@mybox:/home/me/sandbox
$ at -f 1.pl now
Job me.1323356661.a will be run at Thu Dec  8 10:04:21 EST 2011.
me@mybox:/home/me/sandbox
$ at -l
me@mybox:/home/me/sandbox
$ ls -l /tmp/blarney.out
ls: 0653-341 The file /tmp/blarney.out does not exist.