at(1)

NAME
     at, atrun - execute commands at a later time

SYNOPSIS
     at time [month day] [file]

EXAMPLES

     at 2315 Jan 31 myfile
                         # Myfile executed Jan 31 at 11:15 pm

     at 0900             # Job input read from stdin

     at 0711 4 29        # Read from stdin, exec on April 29

DESCRIPTION

     At prepares a file to be executed later at the specified time by creating
     a  special  entry  in  /usr/spool/at. The program atrun should be started
     periodically, for example, every minute by cron.  Atrun checks to see  if
     any files in /usr/spool/at should now be run, and if so, it runs them and
     then puts them in /usr/spool/at/past.  The name of the  file  created  in
     /usr/spool/at by at is YY.DDD.HHMM.UU (where YY, DDD, HH, and MM give the
     time to execute and UU is a unique number).  Note that when  the  command
     runs,  it  will  not  be  able to use stdin or stdout unless specifically
     redirected.  In the first example above, it might  be  necessary  to  put
     >/dev/log  on  some  lines in the shell script myfile. The same holds for
     the commands typed directly to at.

SEE ALSO
     cron(8).