babashka

A sprinkle of Clojure for the command line.

Quickstart

$ bash <(curl -s https://raw.githubusercontent.com/borkdude/babashka/master/install)
$ bb '(vec (dedupe *in*))' <<< '[1 1 1 1 2]'
[1 2]

Rationale

If you're a bash expert, you probably don't need this. But for those of us who scan use a bit of Clojure in their shell scripts, it may be useful.

Properties:

• fast startup time
• code is interpreted by sci, a small Clojure interpreter
• reads from stdin and writes to stdout

Status

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

Installation

Brew

Linux and macOS binaries are provided via brew.

Install:

brew install borkdude/brew/babashka

Upgrade:

brew upgrade babashka

Installer script

Install via the installer script:

$ bash <(curl -s https://raw.githubusercontent.com/borkdude/babashka/master/install)

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

$ bash <(curl -s https://raw.githubusercontent.com/borkdude/babashka/master/install) /tmp

Download

You may also download a binary from Github.

Usage

bb [ --help ] [ -i ] [ -o ] [ -io ] [ --version ] [ -f <file> ] [ expression ]

Type bb --help to see a full explanation of the options.

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 following special forms/macros are supported: anonymous function literals like #(%1 %2), quote, do,if, when, let, and, or, ->, ->>, as->. Anonymous functions literals are allowed with currently up to three positional arguments.

The clojure.core functions are accessible without a namespace alias.

The following Clojure namespaces are required by default and only available through the aliases:

• clojure.string aliased as str
• clojure.set aliased as set
• clojure.java.shell aliases as shell (only sh is available)

From Java the following is available:

• System: getProperty, getProperties, getenv

Examples:

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

$ ls | bb -i '(count *in*)'
12

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

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

$ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
6

$ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'
["reflection.json"]

$ bb '(run! #(shell/sh "touch" (str "/tmp/test/" %)) (range 100))'
$ ls /tmp/test | bb -i '*in*'
["0" "1" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "2" "20" "21" ...]

More examples can be found in the gallery.

Running a file

Babashka expressions may be executed from a file using -f or --file:

bb -f script.clj

Using bb with a shebang also works:

$ cat script.clj
#!/usr/bin/env bb -f

(+ 1 2 3)

$ ./script.clj
6

Test

Test on the JVM:

script/test

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

Build

You will need leiningen and GraalVM.

script/compile

Related projects

• planck
• joker
• closh
• lumo

Gallery

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 https://api.github.com/repos/borkdude/babashka/tags |
jet --from json --keywordize --to edn |
bb '(-> *in* first :name (subs 1))'
"0.0.4"

Get latest OS-specific download url from Github

$ curl -s https://api.github.com/repos/borkdude/babashka/releases |
jet --from json --keywordize |
bb '(-> *in* first :assets)' |
bb '(some #(re-find #".*linux.*" (:browser_download_url %)) *in*)'
"https://github.com/borkdude/babashka/releases/download/v0.0.4/babashka-0.0.4-linux-amd64.zip"

License

Copyright © 2019 Michiel Borkent

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