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Your server taken to the next level with Bash

TAGS:
  • bash
  • bashscripting
  • scripting
  • server

When you need a VPS for your business, you’ll want to ensure that it has the best technology and features. That’s why many developers are using Bash scripting on their servers, a powerful system administration and development tool.

For those new to server management, scripts might seem daunting and scary. However, with a little time, anyone can master them and they should. It will help you manage your server and get more functionality out of it.

What is Bash?

Bash (Bourne-Again Shell) is a command line interface that interacts with operating systems. It is widely available on operating systems and is the default on Linux and macOS operating systems. If you’ve started a Linux VPS and not changed the settings, you’re likely using Bash.

Bash scripting works within a shell, a macro processor, to execute commands on a computer. This tells the computer what it should and should not be doing at any specific moment.

Bash scripts are a series of commands contained in a plain text file. These commands would usually be entered by you on a command line, and also includes some commands that you wouldn’t manually enter. Essentially, anything that you can run on a command line, you can place inside a Bash script. It will execute the same action and the results will be the same.

Therefore, if you have experience working with command lines, you’ll be good at Bash scripting. Even if you have no experience, it’s fairly easy to learn.

When working with Bash scripts, it’s standard practice to use an extension of .sh to identify those text files.

Why use Bash?

Scripting is an essential skill for any system or network engineer. It helps when you have numerous machines or applications that require maintenance and you need to complete predictable tasks repeatedly.

Bash is most useful when deploying changes to applications and operating system changes quickly and efficiently, when you have lots of places to do it. It is also better to use Bash scripting when it’s the default on particular servers, like on Linux VPS servers.

There’s also a lot of free help online for those wanting to use Bash.

Basic Bash scripting

The most basic Bash shell script is creating an output that reads “Hello World”. This uses the echo command. The first step for this is to create a new text file, named hello-world.sh.

Open that file in a text file and enter the following script:

!/bin/bash

echo “Hello World”

Once you’ve saved it in a safe location, you can use the chmod command to execute it with the relative path (e.g. C:\users\admin\bash-scripting\hello-world.sh). Once executed, the output should be:

Hello World

Bash scripting vulnerability

Recently a vulnerability within Bash scripting was found. This affected all Linux/Unix distributions that currently have, or have had, Bash installed. This vulnerability resulted in at least two types of attacks. These attacks were an attempt to install malicious Linux binary files and another attack that infects the server with a malicious Perl script.

Yet you can simply fix this vulnerability with an upgrade/patch. To determine whether this is needed for your server, you can carry out a simple test on your server. To do this run this following command:

$ env x='() { :;}; echo vulnerable’ bash -c “echo this is a test”

If Bash is vulnerable on your server, you’ll receive an output that reads:

vulnerable this is a test

If you are running a version of Bash that isn’t vulnerable you should see something like this:

$ env x='() { :;}; echo vulnerable’ bash -c “echo this is a test” bash: warning: x: ignoring function definition attempt bash: error importing function definition for `x’ this is a test

Do you need help with your Bash scripting?

There’s a lot of online support on Bash scripting that can help you master it. This includes YouTube videos, written tutorials and podcasts. These can be accessed for free.

However, if you are struggling with Bash on your VPS server, you can contact us for technical support. We’re open 24/7 every day of the year.

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