Shulou(Shulou.com)06/03 Report--

The function of the crontab command is to schedule the execution of some commands at regular intervals. There is a crontab file in the / etc directory, where there are some schedulers that the system is running. Each user can set up his own scheduling crontab.

The crontab command has three forms of command line structure:

Crontab [- u user] [file]

Crontab [- u user] [- e |-l |-r]

Crontab-l-u [- e |-l |-r]

In the first command line, file is the name of the command file. If this file is specified on the command line, execute the crontab command and copy the file to the crontabs directory; if the file is not specified on the command line, the crontab command accepts commands typed on the standard input (keyboard) and stores them in the crontab directory as well.

The-r option on the command line deletes the user-defined file crontab from the / usr/spool/cron/crontabs directory

The-l option on the command line displays the contents of the user's crontab file.

Use the command crontab-u user-e to edit the cron (c) job of user user. The user adds or modifies any job request by editing the file.

Execute the command crontab-u user-r to delete all cron jobs for the current user.

After minimizing the installation of centos7.2 today, you find that you cannot save it when you exit crontable. Prompt the following:

[root@localhost] # crontab-e

No crontab for root-using an empty one

Crontab: installing new crontab

"/ tmp/crontab.5wI27z": 1: bad minute

Errors in crontab file, can't install.

Do you want to retry the same edit?

Enter Y or N

Solution:

Echo export EDITOR=/usr/bin/vi > > ~ / .bashrc

It can be solved.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.