Linux rmt Command with Practical Examples

Introduction

In this lab, we will explore the Linux rmt command, which stands for "remote magnetic tape." The rmt command is used to control remote magnetic tape drives over a network connection, allowing you to perform remote backups and restores. We will learn how to use the rmt command in conjunction with the tar command to backup and restore files across a network, as well as how to automate the backup process using a Cron job.

The lab will cover the following steps: Introduction to the rmt command, Backup and Restore Files Using rmt, and Automating Backup with rmt in a Cron Job. The rmt command is typically used for managing remote tape drives, but it can also be used with other storage media like disk or network-attached storage.

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Introduction to the rmt Command

In this step, we will explore the rmt command, which stands for "remote magnetic tape," in the Linux operating system. The rmt command is used to control remote magnetic tape drives over a network connection.

First, let's check the version of the rmt command installed on our system:

rmt --version

Example output:

rmt (GNU tar) 1.34
Copyright (C) 2021 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by John Gilmore and Jay Fenlason.

The rmt command is typically used in conjunction with the tar command to perform remote backups and restores. It allows you to control a remote tape drive as if it were local, making it easier to manage backups across a network.

In the next step, we will learn how to use the rmt command to backup and restore files.

Backup and Restore Files Using rmt

In this step, we will learn how to use the rmt command to backup and restore files over a network.

First, let's create a sample file to work with:

echo "This is a test file." > ~/project/test_file.txt

Now, let's use the tar command with the rmt command to create a backup of the test_file.txt on a remote server:

sudo tar -cvf - ~/project/test_file.txt | rmt remote_host:/path/to/backup.tar

Here's what the command does:

• tar -cvf -: Creates a tarball archive from the test_file.txt file.
• | rmt remote_host:/path/to/backup.tar: Pipes the tarball output to the rmt command, which sends the data to the remote host and saves it as backup.tar.

To restore the file from the remote backup, use the following command:

rmt remote_host:/path/to/backup.tar | sudo tar -xvf -

This command retrieves the backup.tar file from the remote host and extracts the contents to the local system.

Let's verify that the file was restored correctly:

cat ~/project/test_file.txt

Example output:

This is a test file.

Great! You have successfully used the rmt command to backup and restore a file over a network.

Automating Backup with rmt in a Cron Job

In this final step, we will learn how to automate the backup process using the rmt command and a Cron job.

First, let's create a backup script that we can schedule with Cron:

nano ~/project/backup.sh

Add the following content to the script:

#!/bin/bash

## Set the remote host and backup directory
REMOTE_HOST="remote_host"
BACKUP_DIR="/path/to/backup"

## Backup the ~/project directory
sudo tar -czf - ~/project | rmt $REMOTE_HOST:$BACKUP_DIR/project_backup.tar.gz

Save and close the file.

Next, make the script executable:

chmod +x ~/project/backup.sh

Now, let's set up a Cron job to run the backup script daily at 2:00 AM:

sudo crontab -e

Add the following line to the crontab:

0 2 * * * /home/labex/project/backup.sh

This will run the backup.sh script every day at 2:00 AM.

To test the backup, you can manually run the script:

~/project/backup.sh

You should see the backup being created on the remote host.

That's it! You have now automated the backup process using the rmt command and a Cron job.

Summary

In this lab, we explored the Linux rmt command, which is used to control remote magnetic tape drives over a network connection. We learned how to check the version of the rmt command and use it in conjunction with the tar command to perform remote backups and restores. Specifically, we created a sample file, backed it up to a remote server using the rmt command, and then restored the file from the remote backup. The lab provided a practical understanding of how to leverage the rmt command for efficient file management across a network.

Linux Commands Cheat Sheet