Crontab scheduled time execution Program

Crontab-u // set a user's cron service. Generally, the root user needs this parameter when executing this command.
Crontab-l // list the details of a user's cron Service
Crontab-r // Delete the cron service of no user
Crontab-E // edit a user's cron Service

For example, to view your cron settings as root:
Crontab-u root-l

For example, Root wants to delete Fred's cron settings:
Crontab-u Fred-R

When editing the cron service, the edited content has some formats and conventions. Enter:
Crontab-u root-e
In VI editing mode, the edited content must comply with the following format: Reference:
*/1 ***** ls>/tmp/ls.txt

[Root @ centos5 cron] # crontab-e
 
*/1 *** Ping blog.csdn.net/magicbreaker
~
"Crontab. xxxxw48lqg" 1l, 33C written
Crontab: Installing new crontab
[Root @ centos5 cron] # crontab-l
*/1 *** Ping blog.csdn.net/magicbreaker