HP-UX UNIX: Start / Stop and Configure Cron Services

Q. I need to run a backup and other stuff everyday. How do I check and start cron service under HP-UX UNIX operating system? How do I write cron jobs?

A. Cron service is required to run jobs and tasks such as backup.

You must login as the root to run following commands. Each user that is using the cron service must have a cron configuration file in the /var/spool/cron/crontab directory. Also users are permitted if their name appeared in /var/adm/cron/cron.allow file

Task: Find out if cron is running under HP-UX

Type the following command at a shell prompt
# ps -ef | grep cron

Open /etc/rc.config.d/cron file
vi /etc/rc.config.d/cron
Set control variable to 1 to enable cron : CRON=1
Set control variable to 0 to disable : CRON=0
Close and save the file. To start or stop cron you can type the following command:
# /sbin/init.d/cron start <-- start cron
# /sbin/init.d/cron stop <-- stop cron

Task: HP-UX Start cron service

If cron is not running, simply type:
# cron

Task: Edit / create cron jobs

Type the following command to submit a cron job:
# crontab -e
List your cron file:
# crontab -l
Backup all your cron jobs:
# crontab -l > ~/backup.cron.jobs
Remove ALL cron job:
# crontab -r

Task: Crontab file format

Cron file format is as follows:

MIN    HOUR     DATE     MONTH      DAY    /PATH/TO/COMMAND
0-59   0-23      1-31      1-12         0-6     /root/scripts/backup2tape.sh

Easy to remember crontab file format:

* * * * * command to be executed
- - - - -
| | | | |
| | | | ----- Day of week (0 - 7) (Sunday=0 or 7)
| | | ------- Month (1 - 12)
| | --------- Day of month (1 - 31)
| ----------- Hour (0 - 23)
------------- Minute (0 - 59)

To run /root/script/backup at 23:00, every day, enter:
# crontab -e
Append following

0   23  * *  * /root/script/backup

Run foo job very weekday (MON-Fri) at 6am, enter:

0   6  * *  1-5 /root/script/backup

For more information refer to cron and crontab man pages.

Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.