Comment on 2024-09-16 at 10:37 EEST
As of now, every hour is too often. I do it this way:
To create a cron job that runs a script at 9:25 AM, 12:25 PM, 3:25 PM, and 6:25 PM, you can use the following cron expression:
25 9,12,15,18 * * * service network restart
Breakdown of the cron expression:
25: The job runs at 25 minutes past the hour.9,12,15,18: The hours when the job runs (9 AM, 12 PM, 3 PM, 6 PM).*: Every day of the month.*: Every month.*: Every day of the week.
Make sure to replace /path/to/your/script.sh with the actual path to your script. You can add this line to your crontab file by editing it using crontab -e.
Modified openwrt balcony router, so it will restart network service every 4 hours:
Periodic network restart
Restart all your network (lan, wan and wifi) every 3 hours is this:
0 */3 * * * service network restart
Set up cron jobs using command-line interface.
# Edit configuration
crontab -e
# Show configuration
crontab -l
# Apply changes
service cron restart
This will edit the configuraion /etc/crontabs/root file in vi editor.
There should be empty line, according to the manual, Scheduling tasks with cron:
:!: There should be a EOL character on the last line of the crontab file. Just leave an empty line at the end to be sure.
Task specification
Each line is a separate task written in the specification:
* * * * * command to execute
- - - - -
| | | | |
| | | | ----- Day of week (0 - 6) (Sunday =0)
| | | ------- Month (1 - 12)
| | --------- Day (1 - 31)
| ----------- Hour (0 - 23)
------------- Minute (0 - 59)
Examples of time specification: min 0-59 hour 0-23 day/month 1-31 month 1-12 day/week 0-6 Description
*/5 * * * * Every 5 minutes
12 */3 * * * Every 3 hours at 12 minutes
57 11 15 1,6,12 * At 11:57 Hrs on 15th of Jan, June & Dec
25 6 * * 1-5 At 6:25 AM every weekday (Mon-Fri)
0 0 4,12,26 * * At midnight on 4th, 12th and 26th of every month
5,10 9,14 10 * 0,4 At 9:05AM, 9:10AM, 2:05PM and 2:10PM every Sunday and Thursday
:!: 0 (zero) is treated as Sunday. If you set the day of the week to 7, BusyBox will go bonkers and run your command every day.
Table of shortcuts:
Shortcut Equivalent Description
@reboot Run once, at startup
@yearly 0 0 1 1 * Every year
@annually 0 0 1 1 * Every year
@monthly 0 0 1 * * Every month
@weekly 0 0 * * 0 Every week
@daily 0 0 * * * Every day
@midnight 0 0 * * * Every day
@hourly 0 * * * * Every hour
:!: Time shortcuts are not enabled by default. Shortcuts require compiling busybox with FEATURE_CROND_SPECIAL_TIMES enabled in the busybox compile options.
Troubleshooting
You can read log messages with:
logread -e cron
Not all messages are logged, to increase logging change cronloglevel option.