Running a cron job at 2:30 AM everyday
crontab -e
add:
30 2 * * * /your/command
To edit:
crontab -e
Add this command line:
30 2 * * * /your/command
- Crontab Format:
MIN HOUR DOM MON DOW CMD
- Format Meanings and Allowed Value:
MIN Minute field 0 to 59
HOUR Hour field 0 to 23
DOM Day of Month 1-31
MON Month field 1-12
DOW Day Of Week 0-6
CMD Command Any command to be executed.
- Crontab Format:
Restart cron with latest data:
service crond restart
As seen in the other answers, the syntax to use is:
30 2 * * * /your/command
# ^ ^
# | hour
# minute
Following the crontab standard format:
+---------------- minute (0 - 59)
| +------------- hour (0 - 23)
| | +---------- day of month (1 - 31)
| | | +------- month (1 - 12)
| | | | +---- day of week (0 - 6) (Sunday=0 or 7)
| | | | |
* * * * * command to be executed
It is also useful to use crontab.guru to check crontab expressions.
The expressions are added into crontab
using crontab -e
. Once you are done, save and exit (if you are using vi
, typing :x
does it). The good think of using this tool is that if you write an invalid command you are likely to get a message prompt on the form:
$ crontab -e
crontab: installing new crontab
"/tmp/crontab.tNt1NL/crontab":7: bad minute
errors in crontab file, can't install.
Do you want to retry the same edit? (y/n)
If you have further problems with crontab not running you can check Debugging crontab or Why is crontab not executing my PHP script?.