How to schedule a job using crontab

To schedule a job using crontab

Introduction

Cron is used to scheduling commands; it is a standard Unix utility. It helps to maintain the software environment and also known as job crons. Crons is a long-running process to schedule work at a fixed time and date. It is connected to the server to complete the task automatically and also a resourceful tool that helps to save time.

Installation Procedure

Checking the installed OS version

linuxhelp@linuxhelp:~$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 21.04
Release:	21.04
Codename:	hirsute

Log in as a Root user by the following command

linuxhelp@linuxhelp:~$ sudo -s
[sudo] password for linuxhelp:

Editing the crontab file by the following command

root@linuxhelp:/home/linuxhelp# crontab -e
no crontab for root - using an empty one

Select an editor.  To change later, run 'select-editor'.
  1. /bin/nano      <---- easiest
  2. /usr/bin/vim.tiny
  3. /bin/ed

Choose 1-3 [1]: 

On Ubuntu based system it will ask for the editor for the first time to choose one or by default it uses the nano editor. Opened the Crontab file

Add the following lines, this will execute

10 14 * * * touch file
11 14 * * * mkdir folder
12 14 * * * cp file file1

Cron job scheduled

Changing directory by using following command

root@linuxhelp:/home/linuxhelp# cd /root/

Long listing the home directory to view the files created by crontab

root@linuxhelp:~# ls -la
total 40
drwx------  6 root root 4096 Oct  6 13:54 .
drwxr-xr-x 20 root root 4096 Sep  8 16:50 ..
-rw-------  1 root root  627 Oct  6 13:47 .bash_history
-rw-r--r--  1 root root 3106 Aug 15  2019 .bashrc
drwx------  2 root root 4096 Apr 20 16:20 .cache
-rw-r--r--  1 root root    0 Oct  6 13:52 file
-rw-r--r--  1 root root    0 Oct  6 13:54 file1
drwxr-xr-x  2 root root 4096 Oct  6 13:53 folder
drwxr-xr-x  3 root root 4096 Oct  6 13:48 .local
-rw-r--r--  1 root root  161 Sep 16  2020 .profile
-rw-r--r--  1 root root   66 Oct  6 13:48 .selected_editor
drwxr-xr-x  3 root root 4096 Sep  8 17:00 snap

By this schedule a job using crontab comes to end