Bash Scripting - Bash Loops with examples

Bash Loops with examples

Ready to dive into Bash looping? With the popularity of Linux as a free operating system, and armed with the power of the Bash command line interface, one can go further still, coding advanced loops right from the command line, or within Bash scripts.

Harnessing this power, one can manipulate any document, any set of files, or implement advanced algorithms of almost any type and flavor. You are unlikely to run into any limitations if you use Bash as the basis for your scripting, and Bash loops form a powerful part of this.

That said, Bash loops sometimes can be tricky in terms of syntax and surrounding knowledge is paramount. Today we present with you a set of bash loop examples to help you upskill quickly and become Bash loop proficient! Let’s get started!

In this tutorial you will learn:

  • How Bash for, while and until based loops work, with examples
  • How Bash requires terminating of loop-starting statements before the do…done section of the loop can follow, and how this relates to if and other statements
  • How to implement basic and medium advanced bash loops
  • How subshells work and how they can be used inside bash loop scope declarations
  • How to start coding loops defensively, avoiding errors in the output
  • How to code one-liners (a common term used amongst Bash developers) on the command line versus implement the same code in a Bash script
  • How the ; syntax idiom is an important matter when it comes to coding Bash loops, both on the command line and in scripts

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Git Branching Tutorial for beginners

Git Branching Tutorial for beginners

Branching allows git to track multiple lines of development. This essentially allows you to have multiple versions of your project in development at the same time. For example, many projects will choose to have a stable master branch while new features or bug fixes are implemented in a development or testing branch. Once the project organizers are satisfied that the changes made in the development branch have reached the required level of maturity, they may choose to merge those changes into the master branch.

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Batch Convert Audio Files With FFMPEG

How to Batch Convert Music Files with FFMpeg

FFMpeg is at the core of tons of multimedia utilities, but the utility itself doesn’t have the ability to convert multiple files at once. Thankfully, FFMpeg is scriptable, and you can easily set something up quickly with Bash.

In this tutorial you will learn:

  • How to Set Up Your Variables
  • How to Construct the Loop
  • How to Strip Out the File Names
  • How to Put it All Together, and Run

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How to check Bash version

Objective

This article will provide you with the information on how to check bash version on your operating system.

Operating System and Software Versions

  • Operating System: – Distribution Agnostic

Requirements

No special prerequisites are required is required.

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How to create a selection menu using the select statement in Bash shell

How to create a selection menu using the select statement in Bash shell

We all very often use bash scripts to automatize boring and repetitive tasks. Sometimes in our scripts we need to ask
the user to perform one or more choices interactively: in this tutorial we will see how to use the Bash shell select statement to perform such operation in very few lines of code.

In this tutorial you will learn:

  • How to use the Bash select statement
  • How to customize the select menu prompt

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linux-bash-prompt

How to Change Bash Prompt

Default bash command line prompt on many Linux systems is quite minimal. As we will see in this article, it can be easily changed by modifying bash PS{n} variables, so to include information such as display time, load, number of users using the system, uptime and more.

In this tutorial you will learn:

  • What are PS1 and PS2 shell variables
  • How to create custom shell prompts
  • What are the characters we can use to customize a shell prompt

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Bash Script Comment Example

How to write comments in Bash Scripts

Well you have written an awesome Bash script. It works perfectly and perhaps there is no need to add new functionality. Well, maybe not for now, at least! At this stage you are happy with the script. However, after few months you reopen your bash script again to add new feature and you get a headache to figure out on how the script actually works. Hence, you need to spend additional energy and time before you can actually start editing the script in order to add new feature.

Well, at this point you regret that you did not put some comments ( notes ) into the script to remind you of how the bash script is structured. Not only that Bash comments serve as excellent notes for you or anybody else who might work with your script they may be to some extend also used as a basic bash script debugging tool.

In this tutorial you will learn:

  • How to comment on bash command line
  • How to write comment bash scripts
  • How to create multiple line comments

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Hello World example with Ruby.

How to install ruby on RHEL 8 / CentOS 8

Ruby is a very flexible scripting language, it’s popularity well-earned by it’s power. In this tutorial we will install Ruby on a RHEL 8 / CentOS 8, and write the famous “Hello World” program to test that our installation is working as intended. Note however, that with all languages, Ruby’s capabilities are far more than simple text printing on the command line.

In this tutorial you will learn:

  • How to install Ruby with dnf
  • How to get Ruby version information
  • How to write and run the “Hello World” example program in Ruby

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Successful cpan perl module install with cpan on RHEL 8

How to install cpan on RHEL 8 / CentOS 8

Perl is a well-known programming language with long development history. The same long history provides the countless modules written in it, and distributed in various channels throughout the World Wide Web. As with most programming languages, if you implement something that you find useful, and maybe write it in a generic way, there are high chances others would find it useful too.

If you share your work with others, they don’t need to re-implement the wheel, they can spend time on other tools, thus making the community as a whole richer, and we have found the spirit of open source with a short walk. But as many people write perl modules, and perl runs on just about anything, it can be hard to find the module you are looking for, let alone build it in your environment. And that’s where cpan comes into play. CPAN itself is a large perl module repository, the cpan tool is a client that is able to fetch and compile needed modules to the local system.

In this tutorial we’ll install cpan on a RHEL 8 / CentOS 8, run the initial configuration, and install a module with this tool’s help.

In this tutorial you will learn:

  • How to install cpan
  • How to run initial configuration
  • How to install a perl module with cpan

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