Linux crontab Commands

First, Introduction

Crond is a daemon that is used to periodically perform certain tasks or wait for certain events under Linux, similar to Scheduled tasks under Windows, when the operating system is installed, the Service tool is installed by default and the Crond process is started automatically. The Crond process periodically checks to see if there is a task to perform and automatically executes the task if there are tasks to perform.

The task scheduling under Linux is divided into two categories, system task scheduling and user task scheduling. In the/etc directory there is a crontab file, this is the System Task Scheduler configuration file. User Task Scheduler: Users can use the Crontab tool to customize their own scheduled tasks. All user-defined crontab files are saved in the/var/spool/cron directory. Its file name is the same as the user name.

Second, the grammar

Usage:    file    crontab [-u user] [-e |-L |-R]        1003.2)    -e< c9/> (Edit user's crontab)    -L (list user's crontab)-    R    (delete user's crontab)    -I (Prompt before deleting user's crontab)    -S (selinux context)

Description format for each line of tasks in file/etc/crontab:

Minute hour day Month DayOfWeek command

which

 minute------LS/proc >>/tmp/

The command can contain root and run-parts, meaning the following:

Root indicates that running run-parts as rootis followed by a folder, all scripts under that folder are executed

Third, examples

http://blog.csdn.net/ethanzhao/article/details/4406017

Parameters: http://www.cnblogs.com/peida/archive/2013/01/08/2850483.html

Linux crontab Commands