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How to write a Cron Job in Linux?




What is a Cron Job?

Cron is a Linux utility where you can setup a task in your machine to run automatically, if required in a repetitive manner at a specific time and date.
Such a task that you schedule is called a Cron Job.

Here we'll look into how we can setup a cron job in a Linux machine.
Follow the steps bellow.

Step 1 :

Place the script you want to schedule as a Cron Job to one of the following directories in your machine depending on how often you need to repeat the execution of the script.
  • /etc/cron.hourly
  • /etc/cron.daily
  • /etc/cron.weekly
  • /etc/cron.monthly
For example, if you want to schedule your task daily, place the script in the /etc/cron.daily directory.

Step 2 :

Then give correct permissions to the script as follows. Assume script.sh is the script that you need to schedule.

cd /etc/cron.daily
chmod 755 script.sh
 
Step 3 :
Then you should add a new Cron Job to crontab.

crontab -e
 
Step 4 :

Then you will be prompted with your vi editor in the terminal. Type in the following into the editor and to save it hit ESC key, and then type :w followed by :q to exit.

0 0 * * * /etc/cron.daily/script.sh
 
This command will make the Cron Job run every night.
Note : Look at the following to identify the different ways of customizing the command given in Step 4.


Comments

  1. digitalhtsJanuary 11, 2021 at 9:14 PM

    Blog commenting is an excellent. Thank you for sharing this wonderful piece of information and for sharing helpful insights. Otherwise If any one who want to achieve a goal in linux contact us on 9311002620 or https://htsindia.com/Courses/modular-courses/redhat-linux-administration-training-course

    ReplyDelete
  2. Christina BedfordFebruary 22, 2021 at 11:51 PM

    Crontab files are simple text files that have a particular format. Each line of a crontab file follows a particular format as a series of fields, separated by spaces and/or tabs. Each field can have a single value or a series of values. A single cron job should take up exactly one line, but this can be a long line (more than 80 characters).
    for more information click here:how to setup a cron job

    ReplyDelete

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