Bash

Doing Date Math on the Command Line, Part I

If you've ever used a spreadsheet, you've probably used or seen functions for doing date math—in other words, taking one date and adding some number of days or months to it to get a new date, or taking two dates and finding the number days between them. The same thing can be done from the command line using the lowly date command, possibly with a little help from Bash's arithmetic.

Creating the Concentration Game PAIRS with Bash, Part II

Dave finishes up the PAIRS concentration game, only to realize it's too hard to solve! In my last article, I tossed away my PC card and talked about how I was a fan of the British colonial-era writer Rudyard Kipling. With that in mind, I do appreciate that you're still reading my column.

Linux Journal October 2018: Programming

Welcome to the Programming issue, October 2018, of Linux Journal. This month we highlight programming languages new and old including Go, Rust, Clojure and Bash. Take a look at this month's complete line-up: Featured articles in this issue include: * Understanding Bash: Elements of Programming * Getting Started with Rust: Working with Files and Doing File I/O * Introductory Go Programming Tutorial * Creating Linux Command-Line Tools in Clojure

Understanding Bash: Elements of Programming

Ever wondered why programming in Bash is so difficult? Bash employs the same constructs as traditional programming languages; however, under the hood, the logic is rather different. The Bourne-Again SHell (Bash) was developed by the Free Software Foundation (FSF) under the GNU Project, which gives it a somewhat special reputation within the Open Source community. Today, Bash is the default user shell on most Linux installations. Although Bash is just one of several well known UNIX shells, its wide distribution with Linux makes it an important tool to know.

Investigating Some Unexpected Bash coproc Behavior

Recently while refreshing my memory on the use of Bash's coproc feature, I came across a reference to a pitfall that described what I thought was some quite unexpected behavior. This post describes my quick investigation of the pitfall and suggests a workaround (although I don't really recommend using it).

Writing More Compact Bash Code

In any programming language, idioms may be used that may not seem obvious from reading the manual. Often these usages of the language represent ways to make your code more compact (as in requiring fewer lines of code). Of course, some will eschew these idioms believing they represent bad style. Style, of course, is in the eyes of beholder, and this article is not intended as an exercise in defining good or bad style. So for those who may be tempted to comment on the grounds of style I would (re)direct your attention to /dev/null.

Creating the Concentration Game PAIRS with Bash

Exploring the nuances of writing a pair-matching memory game and one-dimensional arrays in Bash. I've always been a fan of Rudyard Kipling. He wrote some great novels and stories, mostly about British colonial-era India. Politically correct in our modern times? Not so much, but still, his books are good fun for readers and still are considered great literature of its time. His works include The Jungle Book, Captains Courageous, The Just So Stories and The Man Who Would Be King, among many others.

Weekend Reading: All Things Bash

Bash is a shell and command language. It is distributed widely as the default login shell for most Linux distributions. We've rounded up some of the most popular Bash-related articles for your weekend reading. Create Dynamic Wallpaper with a Bash Script By Patrick Wheelan Harnessthe power of bash and learn how to scrape websites for exciting new images every morning.  

Building a Bare-Bones Git Environment

How to migrate repositories from GitHub, configure the software and get started with hosting Git repositories on your own Linux server. With the recent news of Microsoft's acquisition of GitHub, many people have chosen to research other code-hosting options. Self-hosted solutions like GitLabs offer a polished UI, similar in functionality to GitHub but one that requires reasonably well-powered hardware and provides many features that casual Git users won't necessarily find useful.

Developing Console Applications with Bash

As a novice software developer, the one thing I look for when choosing a programming language is this: is there a library that allows me to interface with the system to accomplish a task? If Python didn't have Flask, I might choose a different language to write a web application. For this same reason, I've begun to develop many, admittedly small, applications with Bash. Although Python, for example, has many modules to import and extend functionality, Bash has thousands of commands that perform a variety of features, including string manipulation, mathematic computation, encryption and database operations. In this article, I take a look at these features and how to use them easily within a Bash application.

Building a March Madness Bracket in PHP

Jim Hall takes his March Madness script to the next level. Every year in March, my office closely follows the NCAA college basketball tournament, also known as March Madness. You can print out a bracket and make your own predictions as to which team will win at each round. Several of my co-workers take this somewhat seriously, and they always print out their brackets and tack them to their work cubes for all to see. Generally, the winner buys a pizza lunch for the others who played.

All about printf

In my last article, "Fancy Tricks for Changing Numberic Base", I explored the surprising ability of the Linux shell to convert numeric bases on the fly, including this sweet little snippet that converts FF hexadecimal into decimal notation: $ echo $(( 0xFF )) 255

Reading Web Comics via Bash Script

I follow several Web comics. I used to open my Web browser and check out each comic's Web site. That method was fine when I read only a few Web comics, but it became a pain to stay current when I followed more than about ten comics. These days, I read around 20 Web comics. It takes a lot of time to open each Web site separately just to read a Web comic.

Bash Shell Script: Building Your March Madness Bracket

I must admit that I don't really follow basketball. But, I do like to engage with folks at work, and every spring I've always felt a little left out when my work colleagues fill out their NCAA March Madness basketball brackets. If your office is like mine, it seems everyone gets very excited to build their brackets and follow the basketball games and play in an office pool.

The Über-Skeleton Challenge

I received an interesting message from Angela Kahealani with a challenge: "Here's what I'd like to see in Work the Shell: a full-blown shell script template. It should comply with all standards applicable to CLI programs.