Crontab Examples

Some examples to work with contrab

Edit crontab just run

crontab -e

Depends of the Linux distro you have it will show just a blank documents or just a bunch of comments

To show the crontab list run

crontab -l

Remove all crontab jobs (be careful with this command)

crontab -r

Edit the crontab for a specific user. The -u option requires administrator privileges

sudo crontab -u <user> -e

List the crontab for a specific user

sudo crontab -l -u <user>

Remove the crontab for a specific user

sudo crontab -r -u <user>

Crontab entries

Some examples of crontab entries, you can run any shell script and scheduling

Run the shell script on January 2 at 5:30 A.M

30 4 2 1 * /home/user/backup.sh

Run the same script as above, at 12:01 A.M., every Monday in January

01 00 * Jan Monday /home/user/backup.sh

Run every hour, on the hour, from 9 A.M. (09:00) through 6 P.M. (18:00), every day

00 09-18 * * * /home/user/script.sh

Same as the above, but run it every twenty minutes

*/20 09-18 * * * /home/user/script.sh

Run every Monday, at 5 A.M. and 5 P.M:

0 9,17 * * Mon /home/user/script.sh

Run at 10:30 P.M., every weekday:

30 22 * * Mon,Tue,Wed,Thu,Fri /usr/local/bin/backup

Time and date fields

| field        | allowed values        |
| -----        | -----                 |
| minute       | 0-59                  |
| hour         | 0-23                  |
| day of month | 1-31                  |
| month        | 1-12 (or names)       |
| day of week  | 0-7 (0 or 7 is Sunday |

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