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’ crontab files (see cron(1M)). The -r option removes a user’s crontab from the crontab directory.  crontab -l lists 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 determine if the user should be denied access to crontab.  If neither file exists, only root is allowed to submit a job.  If only cron.deny exists and 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 can 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 hyphen (meaning an inclusive range).  Note that the specification of days can 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 runs 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 runs 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 standard input. 

The shell is invoked from your $HOME directory with an initial argument 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. 

EXTERNAL INFLUENCES

International Code Set Support

Single-byte character code sets are supported. 

WARNINGS

Be sure to redirect the standard output and standard error from commands.  If this is not done, any generated output or errors are mailed to the user. 

FILES

/usr/lib/cron main cron directory

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

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

/usr/spool/cron/crontabs directory containing the crontab files

/usr/lib/cron/log accounting information

SEE ALSO

sh(1), cron(1M), queuedefs(4). 

STANDARDS CONFORMANCE

crontab: SVID2, XPG2, XPG3

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992