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A tiny, pure and fast implementation of Clojure in Clojure for shell scripting.


  • pure (no side effects)
  • fast startup time
  • interprets only one form
  • reads from stdin and writes to stdout


If you're a bash expert, you probably don't need this. But for those of us who can use a tiny sprinkle of Clojure on their shell scripts, it may be useful. If most of your script evolves into Clojure, you might want to turn to:


Experimental. Breaking changes are expected to happen at this phase.



Linux and macOS binaries are provided via brew.


brew install borkdude/brew/babashka


brew upgrade babashka

Installer script

Install via the installer script:

$ bash <(curl -s

By default this will install into /usr/local/bin. To change this, provide the directory name:

$ bash <(curl -s /tmp


You may also download a binary from Github.


... | bb [-i] [-o] '<Clojure form>'

There is one special variable, *in*, which is the input read from stdin. The input is read as EDN by default. If the -i flag is provided, then the input is read as a string which is then split on newlines. The output is printed as EDN by default, unless the -o flag is provided, then the output is turned into shell-scripting friendly output. To combine -i and -o you can use -io.

The current version can be printed with bb --version.

Currently only the macros if, when, and, or, -> and ->> are supported.


$ ls | bb -i '*in*'
["LICENSE" "" "bb" "doc" "pom.xml" "project.clj" "reflection.json" "resources" "script" "src" "target" "test"]

$ ls | bb -i '(count *in*)'

$ bb '(vec (dedupe *in*))' <<< '[1 1 1 1 2]'
[1 2]

$ bb '(filterv :foo *in*)' <<< '[{:foo 1} {:bar 2}]'
[{:foo 1}]

Anonymous functions literals are allowed with currently up to three positional arguments.

$ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
$ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'

More examples can be found in the gallery.


Test on the JVM:


Although this tool doesn't offer any benefit when running on the JVM, it is convenient for development.

Test the native version:

BABASHKA_TEST_ENV=native script/test


You will need leiningen and GraalVM.



Here's a gallery of more useful examples. Do you have a useful example? PR welcome!

Shuffle the lines of a file

$ cat /tmp/test.txt
1 Hello
2 Clojure
3 Babashka
4 Goodbye

$ < /tmp/test.txt bb -io '(shuffle *in*)'
3 Babashka
2 Clojure
4 Goodbye
1 Hello

Fetch latest Github release tag

For converting JSON to EDN, see jet.

$ curl -s |
  jet --from json --keywordize --to edn |
  bb '(-> *in* first :name (subs 1))'

Get latest OS-specific download url from Github

$ curl -s |
  jet --from json --keywordize |
  bb '(-> *in* first :assets)' |
  bb '(some #(re-find #".*linux.*" (:browser_download_url %)) *in*)'


Copyright © 2019 Michiel Borkent

Distributed under the EPL License, same as Clojure. See LICENSE.

Can you improve this documentation? These fine people already did:
Michiel Borkent & Peter Strömberg
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