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Create Colorful Stylish Splashy Terminal Apps with gum and Flox

Steve Swoyer | 28 February 2025

For this week’s edition of Fun Package Friday(R)(TM) we’re cuing up software that’s especially near and dear to our hearts. It’s something we happy few in Flox marketing use every. single. day.

It’s gum, a beauty of a utility from the redoubtable folks at Charm. Gum makes it a cinch to add interactive UI elements—like selection menus, input prompts, and progress indicators—to your terminal apps.

If you author shell scripts or create software that runs in a terminal, gum should probably be in your toolkit, especially if you’re building stuff for other people. You want what you build to look and feel good, right?

It gives you a simple, flexible way to add style and splash—what its creators call “glam”—to scripts and apps.

Let’s explore how it can fit into your workflow.

Long-lasting, sugar-free TUI sweetness

Gum is more than just a tool for titivating a terminal user interface (TUI)!

You can use gum to:

• Filter text. The gum filter command supports a fuzzy search capability so users can search interactively through a list of pre-defined options. Think fzf, but with more flexibility when used with or called from other programs.

• Select items. gum choose gives you a way to add interactive selection menus to TUI shell scripts.

• Prompts. Commands like gum input and gum confirm prompt users for input, from free-text responses to simple yes/no confirmations.

• Progress indicators. Flox’s own Ross Turk loves gum for this one especially! Use gum spin and gum progress do display animated spinners or progress bars in your shell scripts.

• Timers. Need to add a countdown to a TUI script? Use gum timer!

Along with gum spin, Flox’s example environments use gum style and gum format to add text formatting, colors, and borders. Because gum reads from stdin and writes to stdout, you can use it with binaries, too.

One pattern is using gum choose or gum input to collect input from users before passing it to a binary.

Try it for yourself. Speaking of which...

Getting It

Let’s go about fetchin’ and usin’ it. Already got Flox? Great. You’re good to go.

You can get our gum package by initializing a Flox environment and installing it from the Flox Catalog.

This is literally as simple as typing:

mkdir bubbalicious && cd bubbalicious
flox init && flox install gum
flox activate

Using It

You got a taste for what gum can do in the screenshot above. If you visit my FloxHub, you’ll discover I’ve made a gum-driven UI + UX a kind of standard feature of the environments I build, especially when I know they’re going to be used by others.

The following is from a Neo4j Flox environment I built for a friend:

Selecting “Yes” takes the user through a configuration process that completely bootstraps a custom Neo4j setup. It captures free-form text input and (as shown above) surfaces prompts.

Once in a Flox subshell, it shows this familiar message:

Here’s the same informational message in a script I created for another friend:

Later in this script’s flow, it showcases gum input, surfacing a selecting menu from which a user can select and install PostgreSQL extensions. Below I’ve selected several extensions that aren’t yet installed:

My script uses gum to prompt the user to confirm their selections, then uses other gum commands (gum progress, gum style, gum format) to display informational text updating the user as to its progress:

(Note: This might be and probably is an anti-pattern. It’s easy to use imperative commands to install PostgreSQL extensions from the command line. It’s even easier to edit Flox’s environment manifest to add them declaratively.)

Ross Turk introduced me to gum and uses it in many of the things he builds. Check out his FloxHub if you’re curious about the many and varied uses he finds for it. Here gum choose powers a menu in his dosgames env so users can select + play productivity-improving games.

One final screenshot: it’s from a Flox environment I built some time ago to bootstrap 1Password and the awscli2 for working with AWS web services. (Like all Flox environments, it still Just Works … 8 months later.)

This has been Fun Package Friday

So that’s gum. It’s one of several gems from the magnificent, the thaumaturgical folks o’er at Charm. Wanna build TUI tools incorporating gum-like features? Check out Charm’s bubble tea framework. Or how about pretty / powerful SSH apps? As you wish: Charm’s got a framework for that, too. They're also the madcap geniuses behind vhs, a tool that records and renders your terminal sessions as GIFs or videos.

Having chewed … not the fat but (echo $GROAN) the gum with you, I now give you … The Weekend.

Happy Hacking!