Bash regexps for beginners with examples

Bash regexps for beginners with examples

Using regular expressions in Bash provides you with plenty of power to parse nearly every conceivable text string (or even full documents), and transform them into nearly any output desirable. If you regularly use Bash, or if you regularly work with lists, textual strings, or documents in Linux, you will find that many jobs can be simplified by learning how to use regular expressions in Bash. Continue reading to learn basic Bash regular expression skills! If you are already familiar with basic regular expressions in Bash or another coding language, see our more advanced bash regular expressions. If not, continue reading to learn basic Bash regular expression skills!

In this tutorial you will learn:

  • How to use regular expressions on the command line in Bash
  • How regular expressions can parse and transform any text string and/or document
  • Basic usage examples of regular expressions in Bash

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Advanced Bash regex with examples

Advanced Bash regex with examples

Using the power of regular expressions, one can parse and transform textual based documents and strings. This article is for advanced users, who are already familiar with basic regular expressions in Bash. For an introduction to Bash regular expressions, see our Bash regular expressions for beginners with examples article instead. Another article which you may find interesting is Regular Expressions in Python.

Ready to get started? Dive in and learn to use regexps like a pro!

In this tutorial you will learn:

  • How to avoid small operating system differences from affecting your regular expressions
  • How to avoid using too-generic regular expression search patters like .*
  • How to employ, or not employ, extended regular expression syntax
  • Advanced usage examples of complex regular expressions in Bash

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Multi-threaded Bash scripting & process management

Multi-threaded Bash scripting & process management at the command line

The things you can do using Bash script are limitless. Once you begin to developed advanced scripts, you’ll soon find you will start to run into operating system limits. For example, does your computer have 2 CPU threads or more (many modern machines have 8-32 threads)? If so, then you will likely benefit from multi-threaded Bash scripting and coding. Continue reading and find out why!

In this tutorial you will learn:

  • How to implement multi-threaded Bash one-liners directly from the command line
  • Why multi-threaded coding almost always can and will increase the performance of your scripts
  • How background and foreground processes work and how to manipulate job queues

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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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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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zenity-logo

How to use graphical widgets in bash scripts with zenity

Zenity is a very useful utility which let us create graphical user interfaces for our shell scripts. Several widgets exists, and can be used by invoking the program with the respective options. The widgets are based on the GTK toolkit, and return the result of the user interaction either on the standard output or as a return code.

In this tutorial you will learn:

  • What are the general zenity options
  • What are the some of the most useful available widgets and how to use them

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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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radiolist-widget

How to use ncurses widgets in shell scripts on Linux

In this tutorial we will learn the basics of the dialog utility, in order to use ncurses widget in our shell scripts. We will see how to install dialog in the most used Linux distributions, some of the common options we can use to alter the behavior of dialog, how to use some widgets; among the others: inputbox, checklist, radiolist and yesno. Finally, we will see how to use the data obtained by the widget processing.

In this tutorial you will learn:

  • How to install the dialog utility on Linux
  • What are the most relevant dialog options
  • How to use the inputbox, checklist, radiolist, passwordbox, msbox, calendar and yesno widgets
  • How to manage data derived from the widget processing

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