CRONTAB(1-SysV)     RISC/os Reference Manual      CRONTAB(1-SysV)



NAME
     crontab - user crontab file

SYNOPSIS
     crontab [file]
     crontab -r
     crontab -l

DESCRIPTION
     crontab copies the specified file, or standard input if no
     file is specified, into a directory that holds all users'
     crontabs.  The -r option removes a user's crontab from the
     crontab directory.  crontab -l will list the crontab file
     for the invoking user.

     Users are permitted to use crontab if their names appear in
     the file /usr/lib/cron/cron.allow. If that file does not
     exist, the file /usr/lib/cron/cron.deny is checked to deter-
     mine if the user should be denied access to crontab. If nei-
     ther file exists, only root is allowed to submit a job.  If
     cron.allow does not exist and cron.deny exists but is empty,
     global usage is permitted.  The allow/deny files consist of
     one user name per line.

     A crontab file consists of lines of six fields each.  The
     fields are separated by spaces or tabs.  The first five are
     integer patterns that specify the following:

          minute (0-59),
          hour (0-23),
          day of the month (1-31),
          month of the year (1-12),
          day of the week (0-6 with 0=Sunday).

     Each of these patterns may be either an asterisk  (meaning
     all legal values) or a list of elements separated by commas.
     An element is either a number or two numbers separated by a
     minus sign (meaning an inclusive range).  Note that the
     specification of days may be made by two fields (day of the
     month and day of the week).  If both are specified as a list
     of elements, both are adhered to.  For example, 0 0 1,15 * 1
     would run a command on the first and fifteenth of each
     month, as well as on every Monday.  To specify days by only
     one field, the other field should be set to * (for example,
     0 0 * * 1 would run a command only on Mondays).

     The sixth field of a line in a crontab file is a string that
     is executed by the shell at the specified times.  A percent
     character in this field (unless escaped by \) is translated
     to a new-line character.  Only the first line (up to a % or
     end of line) of the command field is executed by the shell.
     The other lines are made available to the command as



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CRONTAB(1-SysV)     RISC/os Reference Manual      CRONTAB(1-SysV)



     standard input.

     The shell is invoked from your $HOME directory with an arg0
     of sh.  Users who desire to have their .profile executed
     must explicitly do so in the crontab file.  cron supplies a
     default environment for every shell, defining HOME, LOGNAME,
     SHELL(=/bin/sh), and PATH(=:/bin:/usr/bin:/usr/lbin).

     If you do not redirect the standard output and standard
     error of your commands, any generated output or errors will
     be mailed to you.

FILES
     /usr/lib/cron            main cron directory

     /usr/spool/cron/crontabs spool area

     /usr/lib/cron/log        accounting information

     /usr/lib/cron/cron.allow list of allowed users

     /usr/lib/cron/cron.deny  list of denied users

     /usr/spool/cron/crontabs/periodic
                              special root file

SEE ALSO
     sh(1).
     cron(1M) in the System Administrator's Reference Manual.

WARNINGS
     If you inadvertently enter the crontab command with no
     argument(s), do not attempt to get out with a CTRL-d. This
     will cause all entries in your crontab file to be removed.
     Instead, exit with a DEL.

     A special root file called periodic exists in the
     /usr/spool/cron/crontabs directory.  Do not attempt to
     update this file using the crontab command.  If this is
     done, the root crontab file will actually be overwritten.
     This special file can only be submitted to cron at initiali-
     zation time.













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