bash

58 Articles

Linux Fu: A Warp Speed Prompt

March 20, 2025 by 26 Comments

If you spend a lot of time at the command line, you probably have either a very basic prompt or a complex, information-dense prompt. If you are in the former camp, or you just want to improve your shell prompt, have a look at Starship. It works on the most common shells on most operating systems, so you can use it everywhere you go, within reason. It has the advantage of being fast and you can also customize it all that you want.

What Does It Look Like?

It is hard to explain exactly what the Starship prompt looks like. First, you can customize it almost infinitely, so there’s that. Second, it adapts depending on where you are. So, for example, in a git-controlled directory, you get info about the git status unless you’ve turned that off. If you are in an ssh session, you’ll see different info than if you are logged in locally.

However, here’s a little animation from their site that will give you an idea of what you might expect: Continue reading “Linux Fu: A Warp Speed Prompt” →

Linux Fu: Use The Source (Command), Luke

March 13, 2025 by 12 Comments

You can argue if bash is a good programming language or not, but you can’t argue that it is a programming language. However, there are a few oddities about it that make it different from most other languages you probably know. For one thing, variables are dynamically scoped. Second, you can easily change variables in an upper scope. This leads to a problem when you want to do something like reset your path:

#!/bin/bash
#: This does NOT work
PATH=/usr/bin:/bin

Well, actually, it does work; it just doesn’t work the way you imagine it might. The key is to realize that when you execute our script (say, resetpath), a new copy of bash runs. It inherits all the variables from your shell. Now the script sets PATH for the new copy of bash. Anything else you run in that script will see your change. But when the script exits, the new copy of bash is gone and the old copy sees the same old PATH it always did.

Continue reading “Linux Fu: Use The Source (Command), Luke” →

Building A Raycaster Within Bash

January 16, 2025 by 4 Comments

Wolfenstein 3D was a paradigm-shifting piece of software, using raycasting techniques to create a game with pseudo-3D graphics. Now, [izabera] has done something very similar, creating a raycasting display engine that runs entirely within bash.

The work was developed with an eye cast over an existing raycasting tutorial online. As you might imagine, implementing these graphical techniques in a text console proved difficult. The biggest problem [izabera] encountered was that bash is slow. It’s not supposed to display full frames of moving content at 25+ fps. It’s supposed to display text. Making it display graphics by using tons of colorful characters is really pushing the limits. Bash also doesn’t have any ability to work with floating points, so all the calculations are done with massive integers. Other problems involved the limited ways to read the keyboard in bash, and keeping track of the display as a whole.

It’s neat reading about how this was pulled off—specifically because it was hard. It might not be the kind of project you’d ever implement for serious work, but there are learnings to be had here that you won’t get anywhere else. Code is on Github, while there’s a visual storytelling of how it came together on imgur.

We’ve seen similar work before—with magical 3D graphics generated in Microsoft Excel. Will wonders never cease? We hope not, because we always like to see new ones on the tipsline. Keep us busy!

Optimizing Your Linux Shell Experience

December 22, 2024 by 33 Comments

Are you familiar with Huffman encoding? That’s where you pick shorter codes for more frequent letters. Morse code is the same way, in that the most-used letters are the shortest. [Matheus Richard] had the same idea for optimizing your workflow in the Linux shell. The idea is to measure what commands you use the most and make them shorter.

Continue reading “Optimizing Your Linux Shell Experience” →

Alternatives Don’t Need To Be Bashed

November 26, 2024 by 20 Comments

By default, bash is the most popular command language simply because it’s included in most *nix operating systems. Additionally, people don’t tend to spend a lot of time thinking about whatever their computer uses for scripting as they might for other pieces of software like a word processor or browser. If you are so inclined to take a closer look at this tool that’s often taken for granted, there are a number of alternatives to bash and [monzool] wanted to investigate them closely.

Unlike other similar documentation that [monzool] has come across where the writers didn’t actually use the scripting languages being investigated, [monzool] is planning to use each of these and accomplish specific objectives. This will allow them to get a feel for the languages and whether or not they are acceptable alternatives for bash. Moving through directories, passing commands back and forth, manipulating strings, searching for files, and manipulating the terminal display settings are all included in this task list. A few languages are tossed out before initial testing even begins for not meeting certain specific requirements. One example is not being particularly useful in [monzool]’s preferred embedded environments, but even so there are enough bash alternatives to test out ten separate languages.

Unfortunately, at the end of the day none of the ten selected would make a true replacement for bash, at least for [monzool]’s use case, but there were a few standouts nonetheless. Nutshell was interesting for being a more modern, advanced system and [monzool] found Janet to be a fun and interesting project but had limitations with cross-compiling. All in all though this seemed to be an enjoyable experience that we’d recommend if you actually want to get into the weeds on what scripting languages are actually capable of. Another interesting one we featured a while back attempts to perform as a shell and a programming language simultaneously.

Get Your Lisp On With The Dune Shell

September 20, 2024 by 10 Comments

Lisp is one of those programming languages that seems to keep taunting us for not learning it properly. It is still used for teaching functional languages today. [Adam McDaniel] has an obvious fondness for this fifty-year-old language and has used it in several projects, including their own shell, Dune.

Dune is a shell designed for powerful scripting. Think of it as an unholy combination of bash and Lisp.

Dune is designed to be highly customisable, allowing you to create a super-optimised workstation for your admin and programming tasks. [Adam] describes the front end for Dune as having turned up the cosiness dial to eleven, and we can see that. A cosy home is personalised, and Dune lets you customise everything.

Dune is a useable functional programming environment with a reasonably complete standard library to back it up, which should simplify some of the more complicated sysadmin tasks. [Adam] says the language also supports a few metaprogramming concepts, such as a quote operator, operator overloading, and macro programming. It’s difficult to describe much more about what you can do with Dune, as it’s a general-purpose programming language wrapped in a shell. The possibilities are endless, and [Adam] is looking forward to seeing what you lot out there do with his project!

The shell can be personalised by editing the prelude file, which allows you to overload functions for the prompt text, the incomplete prompt text (so you can implement intelligent completion options), and a function that deals with the formatting of the command response text. [Adam] gives us his personal prelude file, which defines many helper functions displaying useful things such as the current weather, a calendar, and an ASCII art cat. You never know when that might come in handy. This file is written in Lisp, so we reckon that’s where many people will start as they come up the Lisp (re)learning curve before embarking on more involved automation. Dune was written in Rust, so you need that infrastructure to install it with Cargo.

As we said earlier, Lisp is not a new language. We found a hack for porting a Lisp interpreter to any old language and also running Lisp bare metal on a Lisp machine. Finally, [Al] takes a look at some alternative shells.

Blowing Up Shell Scripts

September 18, 2024 by 24 Comments

One of the most universal experiences of any Linux or Unix user is working through a guide or handbook and coming across an almost unbelievably complex line of code meant to be executed with a shell. At the time of encountering a snippet like this it’s difficult to imagine any human ever having written it in the first place, but with some dedication it is possible to tease out what these small bits of code do when they’re typed into the terminal and run (unless it’s something like :(){ :|:& };: but that’s another story entirely). [noperator] recently built a tool which helps users in this predicament understand these shell scripts by expanding them into a more human-intelligible form.

The tool is named sol and does much more than expanding shell one-liners into a readable format. It also provides an interactive shell environment where the user can explore the exploded code in detail, modify it in any way they see fit, and collapse it back down to a single line so it can easily be sent to other users. It can be used with most of the major text editors as well as piped directly to standard input, and has a number of other options as well such as custom configurations and the ability to see non-standard bits of code that might not be compatible from one shell environment to another, as well as helping to translate those bits of code.

[noperator] has made the code available in the linked GitHub page for anyone curious about its use, and has a to-do list for future versions of the tool as well including adding support beyond bash. We’d definitely recommend a tool like this especially if you’re still relatively new to bash scripting (or shell scripting in general) and, as always, we’d just to remind everyone not to blindly copy and paste commands into their terminal windows. If you’re the type of person to go out on a limb and run crazy commands to see what they actually do, though, make sure you’re at least logged into the right computer first.