z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

Appendix I also explains how to set the local time zone with the TZ environment
variable.
For more information about customizing cron, see ″Customizing the cron, uucp,
and mail utilities for a read-only root file system″ and ″Customizing the cron and
uucp Utilities″ in z/OS UNIX System Services Planning.
crontab — Schedule regular background jobs
Format
Description
crontab [–e|–l|–r] [–u user] [file]
crontab creates or changes your crontab entry. The crontab is a system facility that
automatically runs a set of commands for you on a regular schedule. For example,
you might set up your crontab entry so it runs a job every night at midnight, or once
a week during low-use hours. This job could perform regular maintenance chores,
for example, backing up files or getting rid of unnecessary work files.
To set up a crontab entry, use:
crontab file
If you omit the file argument, crontab takes input from standard input (stdin).
Note: In this mode, you must provide your entire crontab file. This replaces any
other existing crontab entries. If you issue crontab with no options, do not
enter the end-of-file character or you will end up with an empty crontab file.
Press INTERRUPT instead.
Input consists of six fields, separated by blanks. All blank lines and any input that
contains a # as the first non-blank character are ignored. The first five give a date
and time in the following form:
v A minute, expressed as a number from 0 through 59
v An hour, expressed as a number from 0 through 23
v A day of the month, expressed as a number from 1 through 31
v A month of the year, expressed as a number from 1 through 12
cron daemon
v A day of the week, expressed as a number from 0 through 6 (with 0 standing for
Sunday)
Important Note: All times use a system default time zone. Your system
administrator can tell you what it is. The cron daemon does not
use the value of the environment variable TZ when crontab is
invoked.
Any of these fields may contain an asterisk (*) standing for all possible values. For
example, if you have an * as the day of the month, the job runs every day of the
month. A field can also contain a set of numbers separated by commas, or a range
of numbers, with the first number followed by a minus sign – followed by the second
number. If you give specific days for both day of the month and day of the week,
the two are ORed together. Here are some examples:
Chapter 2. Shell command descriptions 171