49 lines
1.6 KiB
Markdown
49 lines
1.6 KiB
Markdown
# cron
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```
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# * * * * * command to execute
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# │ │ │ │ │
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# │ │ │ │ │
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# │ │ │ │ └───── day of week (0 - 6) (0 to 6 are Sunday to Saturday, or use names; 7 is Sunday, the same as 0)
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# │ │ │ └────────── month (1 - 12)
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# │ │ └─────────────── day of month (1 - 31)
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# │ └──────────────────── hour (0 - 23)
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# └───────────────────────── min (0 - 59)
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```
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See also
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- [wikipedia/cron](http://en.wikipedia.org/wiki/Cron)
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## cron directories
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You can create directories that run cron commands. Taken from the `Ubuntu`
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distro:
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```txt
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# /etc/crontab: system-wide crontab
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# Unlike any other crontab you don't have to run the `crontab'
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# command to install the new version when you edit this file
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# and files in /etc/cron.d. These files also have username fields,
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# that none of the other crontabs do.
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SHELL=/bin/sh
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PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
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# m h dom mon dow user command
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17 * * * * root cd / && run-parts --report /etc/cron.hourly
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25 6 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
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47 6 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
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52 6 1 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
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```
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## run every weekday at midnight
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```sh
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0 0 * * 0-5
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```
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## edit cronjobs
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```sh
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$ sudo crontab -e
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```
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## user crontab lcation
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`/var/spool/cron/crontabs` |