Bash-like shell based on Clojure
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closh - Bash-like shell based on Clojure

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Closh combines the best of traditional unix shells with the power of Clojure. It aims to be a modern alternative to bash.

Demo showing how to execute commands and using Clojure to manipulate outputs in shell:

closh demo screencast

Why try to reinvent bash?

  • Bash has obscure syntax for non-trivial operations and lots of WTF moments.
  • It treats everything as text while we mostly need to manipulate structured information.
  • It is a large codebase which makes it difficult to hack on it and try innovative ideas. Which is one of the reasons why the shell did not improve much in recent decades.
  • Traditional shells are limited in terms of presentation and discoverability, what if we could bring back richer environment as imagined by lisp machines?

Why shell based on Clojure(Script)?

  • Clojure's has a simple syntax and well-thought design which makes it pleasurable to work with.
  • Its extensive collection of powerful functions for data manipulation is suitable to provide solutions for daily tasks.
  • Write shell scripts in a language you use daily for development so you don't have to google arcane shell constructs every time you need to do anything but simplest tasks.
  • Less amount and more composable code allows to experiment with new features and ideas.

Warning: Closh is still in a early stage and under a heavy development, has many rough edges and is subject to change a lot. Closh is tested on Linux, should run on macOS too. Windows who knows.

Community and Contribution

If you have feedback about a specific feature or found a bug please open an issue.
Use reddit for general discussion and to share scripts and workflows. Chat room is on gitter.

If you would like to contribute take look at open issues. Leave a comment if you find anything interesting and we can improve the project together.


Windows is currently NOT supported! If you know your way around with Windows, we need your help (see #54).

Install closh (requires node.js version 9.x):

npm install -g closh

If you get a permission error then try:

npm install -g closh --unsafe-perm

To install development version from master branch:

npm i -g dundalek/closh

Quick Start

Start the shell:


Run simple commands like you are used to:

$ echo hi

$ git status

$ ls -l *.json

Commands starting with a parenthesis are evaluated as Clojure code:

$ (+ 1 2)
; => 3

The power comes from combining shell commands and Clojure:

$ echo hi | (clojure.string/upper-case)
; => HI

$ ls *.json |> (reverse)

; Count number of files grouped by first letter sorted by highest count first
$ ls |> (group-by first) | (map #(update % 1 count)) | (sort-by second) | (reverse)

If you like closh you can set it as your default shell (afterwards you need to log out and log back in):

which closh | sudo tee -a /etc/shells
chsh -s $(which closh)



Upcoming release v0.3

Terminal UI improvements and ideas

Explore innovate UI ideas, explore what a shell could become and all possibilities within an ASCII terminal. The goal is to reimagine what people think a command line interface is without having to lose its core power.

More UI exploration

Explore if we could take shell power and functionality and lift it from the boundaries set by ASCII terminals.

Stabilization and performance

I hope that new UI ideas above will get people excited and interested. After that we should work on stabilization and adding all the remaining features people are used to from traditional shells.

  • Script mode
  • Implement a low-level native pipeline library to improve performance
  • Make it more robust and better error handling
  • Job control


Clone the repo and install dependencies

git clone
cd closh
npm install

Run the app

npm start

Run in dev mode reloading on changes

npm run dev

Run tests once

lein test

Re-run tests on change

lein test-auto

Copyright & License

Copyright (c) Jakub Dundalek and contributors

Distributed under the Eclipse Public License 1.0 (same as Clojure).

Logo created by @batarian71 under CC BY 4.0.