NAME

crontab − user crontab file

SYNOPSIS

crontab [ filename ]
crontab −e [username]
crontab −r [username]
crontab −l [username]

AVAILABILITY

SUNWcsu

DESCRIPTION

crontab copies the specified file, or the standard input if no file is specified, into a directory that holds all users’ crontabs. 

Users are permitted to use crontab if their names appear in the file /etc/cron.d/cron.allow. If that file does not exist, the file /etc/cron.d/cron.deny is checked to determine if the user should be denied access to crontab.  If neither 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.  Other lines are made available to the command as standard input.  Any line beginning with a # is a comment and will be ignored. 

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), TZ, and PATH(=/sbin:/usr/bin:/usr/sbin:/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. 

OPTIONS

−e The −e option edits a copy of the current user’s crontab file, or creates an empty file to edit if crontab does not exist.  When editing is complete, the file is installed as the user’s crontab file.  If a username is given, the specified user’s crontab file is edited, rather than the current user’s crontab file; this may only be done by a privileged user.  The environment variable EDITOR determines which editor is invoked with the −e option.  The default editor is ed(1). 

−l crontab −l lists the crontab file for the invoking user.  Only a privileged user can specify a username following the −r or −l options to remove or list the crontab file of the specified user. 

−r The −r option removes a user’s crontab from the crontab directory. 

FILES

/etc/cron.d main cron directory

/etc/cron.d/cron.allow list of allowed users

/etc/cron.d/cron.deny list of denied users

/var/cron/log accounting information

/var/spool/cron/crontabs
spool area

SEE ALSO

atq(1), atrm(1), ed(1), sh(1), cron(1M), su(1M)

NOTES

If you inadvertently enter the crontab command with no argument(s), do not attempt to get out with a CTRL-D.  This removes all entries in your crontab file.  Instead, exit with a CTRL-C. 

If a privileged user modifies another user’s crontab file, resulting behavior may be unpredictable.  Instead, the privileged user should first su(1M) to the other user’s login before making any changes to the crontab file. 

SunOS 5.2  —  Last change: 14 Sep 1992