{"id":3030,"date":"2023-12-22T02:42:00","date_gmt":"2023-12-22T07:42:00","guid":{"rendered":"https:\/\/www.both.org\/?p=3030"},"modified":"2024-06-03T15:09:20","modified_gmt":"2024-06-03T19:09:20","slug":"programming-bash-1-introducing-a-new-series","status":"publish","type":"post","link":"https:\/\/www.both.org\/?p=3030","title":{"rendered":"Programming Bash #1 – Introducing a New Series"},"content":{"rendered":"
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\r\n \r\n <\/i>\r\n <\/a>\r\n <\/span>\r\n<\/div><\/div>\n

I use Bash all the time, in part because it is the default shell for most Linux distributions, including Fedora and CentOS, the ones I normally use. However I also use Bash because it is an excellent shell and it has a large number of features to make life easier for the Lazy SysAdmin.<\/p>\n\n\n\n

Features like tab completion, command line recall and editing, shortcuts like aliases, and more all contribute to its value as a powerful shell. One of my favorite Bash features is that, although it uses Emacs mode for command line editing by default, that can be changed to Vi mode so that I can use editing commands that are already part of my muscle memory.<\/p>\n\n\n\n

But if we think of Bash solely as a shell we miss much of its true power. While researching Bash for my three-volume Linux self-study course1<\/a><\/sup>, upon which this series of articles is based, I learned things about Bash that I never knew in over 20 years of working with Linux. Some of these new bits of knowledge relate to its use as a programming language. Bash is a powerful programming language, one perfectly designed for use on the command line and in shell scripts. For this series we are exploring its use on the command line interface (CLI).<\/p>\n\n\n\n

Let\u2019s start with a few basics.<\/p>\n\n\n\n

What is a shell?<\/h2>\n\n\n\n

A shell is the command interpreter for for the operating system. Each of the many shells available for Linux interprets the commands typed by the user or SysAdmin into a form usable by the operating system. When the results are returned to the shell program, it displays them on the terminal. All of the shells with which I am familiar are also programming languages.<\/p>\n\n\n\n

Bash stands for Bourne Again Shell because the Bash shell is based upon the older Bourne shell which was written by Steven Bourne in 1977. Many other shells are available.2<\/a><\/sup> The four I list here are the ones I encounter most frequently but many others exist.<\/p>\n\n\n\n