[ Thanks to LinucksGirl for this link.
]
“Sometimes you may need to run a job just once, rather
than regularly. For this you use the at command. The commands to be
run are read from a file specified with the -f option, or from
stdin if -f is not used. The -m option sends mail to the user even
if there is no stdout from the command. The -v option displays the
time at which the job will run before reading the job”