Install crontab:
yum install crontabs
Basic cron service control command:
code
- /sbin/service crond start //Start the service
- /sbin/service crond stop //Close service
- /sbin/service crond restart //Restart service
- / sbin/service crond reload //Reload the configuration
Check the crontab service status: service crond status
Manually start the crontab service: service crond start
Check whether the crontab service has been set to start at boot. Execute command: ntsysv
Add automatic startup at boot: chkconfig --level 35 crond on
If you want to know more about the chkconfig --level command, http://www.cnblogs.com/panjun-Donet/archive/2010/08 /10/1796873.html Explain in more detail
crontab command introduction
code
- Function description: Set timer.
- Syntax: crontab [-u
][Configuration file] or crontab [-u ][-elr] - Additional explanation: cron is a resident service that provides a timer function that allows users to execute preset instructions or programs at a specific time. As long as the user can edit the timer's configuration file, the timer function can be used. The configuration file format is as follows:
- Minute Hour Day Month DayOFWeek Command
- Parameters:
- -e Edit this The user's timer settings.
- -l List the timer settings for this user.
- -r Delete the timer settings for this user.
- -u
Specify the user name to set the timer.
crontab format
code
- Basic format:
- * * *
- The first column represents minutes 1 to 59. Each minute is represented by * or */1
- The second column represents hours 1 to 23 (0 represents 0 o'clock)
- 3 columns represent the days 1 to 31
- The 4th column represents the months 1 to 12
- The 5th column identifies the week 0 to 6 (0 means Sunday)
- The command to run in column 6
- # Use the hash sign to prefix a comment
- # +———— - minute (0 – 59)
- # | +————- hour (0 – 23)
- # | | +————- day of month (1 – 31)
- # | | | +——- month (1 – 12)
- 0 – 7) ( Sunday=0 or
- 7)
- # | | |
- mand to be executed crontab file Some examples:
- code
- 30 21 * * * /etc/init.d/nginx restart
- Every night 21
- :30Restart nginx.
- 45
- 41 ,10,22 * * /etc/init. d/nginx restart
- Every month 1
- , 10, 22 on 4 : 45Restart nginx.
- 10
- 1 * * 6,0 /etc/init.d/nginx restart
- Every Saturday and Sunday 1
- : 10Restart nginx.
- 0
- ,3018 -23 * * * /etc/init.d/nginx restart
- Every day 18
- : 00 to 23 : Every between 00 30Restart nginx.
- 0
- 23 * * 6 /etc/init.d/nginx restart
- Every Saturday 11
- : 00 pm restart nginx.
- * */1
- * * * /etc/init.d/nginx restart
- Restart nginx every hour
- * * * /etc/init.d/nginx restart
- Restart nginx every hour between 11 and morning7
- 0
- 11 4 * mon-wed /etc/init.d/nginx restart
- The
- 4 of every month and every Monday to Wednesday
- 11 points Restart nginx
- 1 jan * /etc/init.d/nginx restart
- Restart nginx at 4 on January 1st
- */
- 3 0 * * * * /usr/sbin/ntpdate 210.72.145.20
- Synchronize time every half hour
- Apply to thinkphp
Original link: http://164418960.iteye.com/blog/2170536
The above introduces the Linux Crontab command, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.

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