Bash crontab Command - Schedule Tasks — Bash interactive lesson

Understanding Cron and Crontab

The cron system is a time-based job scheduler in Unix-like operating systems.

It automates the execution of tasks (known as cron jobs) at specified intervals.

While cron is the background service that runs these tasks, crontab is the command used to manage them.

There is no direct "cron" command; instead, you use crontab to set up and control cron jobs.

The crontab command allows you to define scheduled tasks.

These tasks are specified in a crontab file, which is a simple text file containing a list of commands meant to be run at specified times.

The basic syntax of the crontab command is:

crontab [options]

Cron jobs are defined using a specific syntax in the crontab file. Each line in the file represents a task and follows this format:

* * * * * command_to_execute

Each asterisk can be replaced with a specific value or range to schedule the command at specific times.

To run a script every day at midnight, you would use:

0 0 * * * /path/to/script.sh

This entry will execute /path/to/script.sh every day at 00:00 (midnight).

Cron jobs are commonly used to