Introduction to Bash
What is Bash and what is used for.
Bash stands for Bourne Again SHell. It is a Unix shell and command language widely used by Linux users. A shell is essentially a command line interpreter which provides you with an interface to access the services of the operating system.
Bash is a command processor that executes commands read from standard input or from a file. It also reads and executes commands from a script (or file).
Some key points about Bash:
Bash is a sh-compatible command language interpreter. This means that most Bourne shell scripts can be run with Bash without any modifications.
Bash can be run both as an interactive login shell and as a non-interactive shell script.
Bash reads commands from .bashrc when it is invoked as an interactive login shell and from .bash_profile when invoked as a non-login shell. This allows you to customize your Bash environment.
Bash supports command line editing, history substitution, programmable command completion, shell functions and shell scripts.
Bash has built-in commands like cd, echo, exit, unset, alias etc. It also has conditional statements if/else, for/while loops, functions etc.
Bash scripts use the .sh extension by default.
Here are the details about when Bash was created and the platforms that can run Bash:
Bash was created by Brian Fox in 1989. It was developed as part of the Free Software Foundation's GNU project.
The primary goal of creating Bash was to make the powerful Unix shell available to Linux and other free operating systems that were emerging at the time.
Bash can run on any Unix-like system including Linux, Mac OS X, BSD, and Solaris. It has also been ported to Windows.
Bash is the default shell on most Linux distributions and on Mac OS X.
Bash can also run on other Unix-like operating systems like HP-UX, AIX and IBM z/OS Mainframes. However, it may require additional software to be installed first on these platforms.
Bash has evolved a lot since its initial release in 1989. The latest stable version as of 2022 is Bash 5.1.
Here are reasons why someone should learn Bash and the motivation behind it:
Bash is the default shell on most Linux distributions and on Mac OS X. So if you are using a Linux system or Mac, learning Bash will allow you to effectively interact with the operating system through the command line.
Bash scripting allows you to automate repetitive tasks and customize your environment. Once you learn the basics of Bash scripting, you can write scripts to automate mundane system administration tasks or tasks you perform frequently. This saves a lot of time and effort.
Bash is a very popular scripting language. Knowing Bash can improve your employability as a Linux system administrator or DevOps engineer. Many job postings require or prefer Bash scripting skills.
Bash has a relatively small learning curve compared to other programming languages. If you know the basics of programming, you can pick up Bash scripting quickly.
Learning Bash helps build a solid foundation for learning other shells like Zsh, Ksh, and Csh. It also helps in learning full-fledged programming languages like C, Perl, Python etc.
Bash comes built-in with most Linux systems, so there is no additional software required to start learning and practicing Bash scripting.
Time to learn
To go from a beginner to an intermediate level in Bash, where you can write simple but effective Bash scripts, around 30-50 hours of focused learning should suffice. This depends a lot on your previous experience and learning style.
This lecture focused on setting realistic goals and expectations for how long it takes to learn Bash. It recommended starting with the basics like navigating files and using variables and commands. Then progressing to conditional statements, loops and functions.
The most important thing is to practice what you learn by writing small Bash scripts and debugging them. More advanced topics will come later as your skills progress.
To fully learn Bash scripting, we will create more comprehensive articles beyond this introductory lecture. The next articles will:
Cover fundamentals in more depth with practical examples
Provide exercises for you to reinforce the concepts through practice
Introduce additional topics and techniques in a progressive manner
Use proper syntax highlighting and code formatting for readability
The goal of creating a series of 20 articles is to systematically walk you through everything from basic Bash skills to advanced scripting capabilities. Each article will build upon the previous ones to develop your Bash proficiency over time.
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