CentOS crontab Timer Execute script auto back up file sync data

This article explains the timing plan from the installation to an automatic duty example
Install Crontab:
[Root@centos ~]# Yum Install Vixie-cron
[Root@centos ~]# Yum Install Crontabs

Description
Vixie-cron packages are Cron's main programs;
The Crontabs package is a program used to install, uninstall, or enumerate the tables used to drive the cron daemon.
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Cron is a built-in service for Linux, but it does not automatically get up, you can start and close the service in the following ways:
/sbin/service crond Start//boot service
/sbin/service Crond Stop//Off service
/sbin/service crond Restart//Restart service
/sbin/service Crond Reload//Reload Configuration

See Crontab Service Status: Service Crond status
Manually start the Crontab service: Service Crond start
To see if the Crontab service is set to boot, execute command: NTSYSV
Join the boot auto start:
Chkconfig–level Crond on

1,crontab command
Feature Description: Set timer.
Syntax: crontab [-u < user name >][configuration file] or crontab [-u < user name >][-ELR]
Supplemental Note: Cron is a resident service that provides the function of timers to allow users to execute preset instructions or programs at a specific time. The timer function can be used as long as the user edits the timer's configuration file. The configuration file format is as follows:
Minute Hour Day Month DayOfWeek Command

Parameters
-e Edit the user's timer settings.
-l lists the user's timer settings.
-R Deletes the user's timer settings.
-u< User name > Specifies the name of the user to set the timer.

2,crontab format
Basic format:
* * * * command
Time-sharing and Lunar Week command

The 1th column represents minutes 1~59 per minute or/1
The 2nd column represents the hour 1~23 (0 for 0 points)
The 3rd column represents the date 1~31
The 4th column represents the month 1~12
The 5th list of the week 0~6 (0 for Sunday)
6th column the command to run
Some examples of crontab files:
* * * * * * * */USR/LOCAL/ETC/RC.D/LIGHTTPD Restart the above example shows 21:30 restart Apache per night.

4 1,10,22 * * */USR/LOCAL/ETC/RC.D/LIGHTTPD Restart the above example shows 1, 10, 22nd 4:45 restart Apache.

1 * * * 6,0/USR/LOCAL/ETC/RC.D/LIGHTTPD Restart the above example shows that every Saturday, Sunday 1:10 restart Apache.

0,30 18-23 * * * * */USR/LOCAL/ETC/RC.D/LIGHTTPD Restart the above example indicates that Apache is restarted every 30 minutes between 18:00 and 23:00 every day.

0 * * * * 6/USR/LOCAL/ETC/RC.D/LIGHTTPD Restart the above example indicates that the 11:00 PM restarts Apache every Saturday.

/1 * */USR/LOCAL/ETC/RC.D/LIGHTTPD restart restart Apache every hour

23-7/1 * * * * * * */usr/local/etc/rc.d/lighttpd restart 11 o'clock to the morning 7, restart Apache every hour.

0 4 * mon-wed/usr/local/etc/rc.d/lighttpd Restart monthly 4th and restart Apache every Monday to Wednesday 11.

0 4 1/USR/LOCAL/ETC/RC.D/LIGHTTPD * Restart January 1 restart Apache at 4 points

/30 * * */usr/sbin/ntpdate 210.72.145.44 sync time every half hour

The CRONTAB command has 3 main parameters:
-E: Edit the user's crontab.
-L: Lists the contents of the user's crontab.
-r: Deletes the user's crontab content.

Execute CRONTAB-E, will automatically open the editor, you can edit your own crontab file, syntax and/etc/crontab file, the difference is just, do not have to point out the execution of the user, edited after save. Crontab-l used to view the internal energy of their crontab files, crontab-r delete their cron

Well-known data is very important
Write a simple MySQL data file backup

VI write a file with the end of. Sh
Within the same

#!/bin/bash
# #wholly backup
tar-czpf/var/database/mysql/db_ ' Date +%y%m%d '. Tar.gz/var/lib/mysql

command
crontab-e 

new Open VI content for
2 * * * root/usr/loal/script/backup  Script path
save exit

service Crond  Status See if it is running state  

to complete a simple backup script here