1. Managing Terminals and Modems (Overview)
2. Setting Up Terminals and Modems (Tasks)
3. Managing Serial Ports With the Service Access Facility (Tasks)
4. Managing System Resources (Overview)
5. Displaying and Changing System Information (Tasks)
7. Managing UFS Quotas (Tasks)
8. Scheduling System Tasks (Tasks)
Creating and Editing crontab Files (Task Map)
Ways to Automatically Execute System Tasks
For Scheduling Repetitive Jobs: crontab
For Scheduling a Single Job: at
Scheduling a Repetitive System Task (cron)
How the cron Daemon Handles Scheduling
Syntax of crontab File Entries
Creating and Editing crontab Files
How to Create or Edit a crontab File
How to Verify That a crontab File Exists
Controlling Access to the crontab Command
How to Deny crontab Command Access
How to Limit crontab Command Access to Specified Users
How to Verify Limited crontab Command Access
Using the at Command (Task Map)
Scheduling a Single System Task (at)
Controlling Access to the at Command
How to Deny Access to the at Command
How to Verify That at Command Access Is Denied
9. Managing System Accounting (Tasks)
10. System Accounting (Reference)
11. Managing System Performance (Overview)
12. Managing System Processes (Tasks)
13. Monitoring System Performance (Tasks)
14. Troubleshooting Software Problems (Overview)
16. Managing Core Files (Tasks)
17. Managing System Crash Information (Tasks)
18. Troubleshooting Miscellaneous Software Problems (Tasks)
19. Troubleshooting File Access Problems (Tasks)
20. Resolving UFS File System Inconsistencies (Tasks)
By default, crontab file protections are set up so that you cannot inadvertently delete a crontab file by using the rm command. Instead, use the crontab -r command to remove crontab files.
By default, the crontab -r command removes your own crontab file.
You do not have to change the directory to /var/spool/cron/crontabs (where crontab files are located) to use this command.
Become superuser or assume an equivalent role to remove a crontab file that belongs to root or another user. Roles contain authorizations and privileged commands.
You do not need to become superuser or assume an equivalent role to remove your own crontab file.
$ crontab -r [username]
where username specifies the name of the user's account for which you want to remove a crontab file. Removing crontab files for another user requires superuser privileges.
Caution - If you accidentally type the crontab command with no option, press the interrupt character for your editor. This character allows you to quit without saving changes. If you instead saved changes and exited the file, the existing crontab file would be overwritten with an empty file. |
# ls /var/spool/cron/crontabs
Example 8-5 Removing a crontab File
The following example shows how user smith uses the crontab -r command to remove his crontab file.
$ ls /var/spool/cron/crontabs adm jones lp root smith sys uucp $ crontab -r $ ls /var/spool/cron/crontabs adm jones lp root sys uucp