babashka/README.md

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A Clojure [babushka](https://en.wikipedia.org/wiki/Headscarf) for the grey areas of Bash.

<blockquote class="twitter-tweet" data-lang="en">
    <p lang="en" dir="ltr">Life's too short to remember how to write Bash code. I feel liberated.</p>
    &mdash;
    <a href="https://github.com/laheadle">@laheadle</a> on Clojurians Slack
</blockquote>

## Quickstart

``` shellsession
$ bash <(curl -s https://raw.githubusercontent.com/borkdude/babashka/master/install)
$ ls | bb --time -i '(filter #(-> % io/file .isDirectory) *input*)'
("doc" "resources" "sci" "script" "src" "target" "test")
bb took 4ms.
```

## Rationale

The sweet spot for babashka is executing Clojure snippets or scripts in the same
space where you would use Bash.

As one user described it:

> I’m quite at home in Bash most of the time, but there’s a substantial grey area of things that are too complicated to be simple in bash, but too simple to be worth writing a clj/s script for. Babashka really seems to hit the sweet spot for those cases.

Goals:

* Fast startup / low latency. This is achieved by compiling to native using [GraalVM](https://github.com/oracle/graal).
* Familiarity and portability. Keep migration barriers between bash and Clojure as low as possible by:
  - Gradually introducing Clojure expressions to existing bash scripts
  - Scripts written in babashka should also be able to run on the JVM without major changes.
* Multi-threading support similar to Clojure on the JVM
* Batteries included (clojure.tools.cli, core.async, ...)

Non-goals:

* Performance
* Provide a mixed Clojure/bash DSL (see portability).
* Replace existing shells. Babashka is a tool you can use inside existing shells like bash and it is designed to play well with them. It does not aim to replace them.

Babashka uses [sci](https://github.com/borkdude/sci) for interpreting Clojure. Sci
implements a subset of Clojure and is not as performant as compiled code. If your script is taking more than a few seconds,  Clojure on the JVM may be a better fit.

Read more about the differences with Clojure [here](#differences-with-clojure).

## Status

Experimental. Breaking changes are expected to happen at this phase. Keep an eye
on [CHANGES.md](CHANGES.md) for a list of breaking changes.

## Examples

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

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

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

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

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

$ ls | bb -i '(filterv #(re-find #"README" %) *input*)'
["README.md"]

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

$ bb -O '(repeat "dude")' | bb --stream '(str *input* "rino")' | bb -I '(take 3 *input*)'
("duderino" "duderino" "duderino")
```

More examples can be found in the [gallery](#gallery).

## Installation

### Brew

Linux and macOS binaries are provided via brew.

Install:

    brew install borkdude/brew/babashka

Upgrade:

    brew upgrade babashka

### Arch (Linux)

`babashka` is [available](https://aur.archlinux.org/packages/babashka-bin/) in the [Arch User Repository](https://aur.archlinux.org). It can be installed using your favorite [AUR](https://aur.archlinux.org) helper such as
[yay](https://github.com/Jguer/yay), [yaourt](https://github.com/archlinuxfr/yaourt), [apacman](https://github.com/oshazard/apacman) and [pacaur](https://github.com/rmarquis/pacaur). Here is an example using `yay`:

    yay -S babashka-bin

### Windows

On Windows you can install using [scoop](https://scoop.sh/) and the
[scoop-clojure](https://github.com/littleli/scoop-clojure) bucket.

### Installer script

Install via the installer script:

``` shellsession
$ 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:

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

### Download

You may also download a binary from
[Github](https://github.com/borkdude/babashka/releases). For linux there is a
static binary available which can be used on Alpine.

## Usage

``` shellsession
Usage: bb [ -i | -I ] [ -o | -O ] [ --stream ] [--verbose]
          [ ( --classpath | -cp ) <cp> ] [ --uberscript <file> ]
          [ ( --main | -m ) <main-namespace> | -e <expression> | -f <file> |
            --repl | --socket-repl [<host>:]<port> ]
          [ arg* ]

Options:

  --help, -h or -?    Print this help text.
  --version           Print the current version of babashka.

  -i                  Bind *input* to a lazy seq of lines from stdin.
  -I                  Bind *input* to a lazy seq of EDN values from stdin.
  -o                  Write lines to stdout.
  -O                  Write EDN values to stdout.
  --verbose           Print entire stacktrace in case of exception.
  --stream            Stream over lines or EDN values from stdin. Combined with -i or -I *input* becomes a single value per iteration.
  --uberscript <file> Collect preloads, -e, -f and -m and all required namespaces from the classpath into a single executable file.

  -e, --eval <expr>   Evaluate an expression.
  -f, --file <path>   Evaluate a file.
  -cp, --classpath    Classpath to use.
  -m, --main <ns>     Call the -main function from namespace with args.
  --repl              Start REPL. Use rlwrap for history.
  --socket-repl       Start socket REPL. Specify port (e.g. 1666) or host and port separated by colon (e.g. 127.0.0.1:1666).
  --time              Print execution time before exiting.
  --                  Stop parsing args and pass everything after -- to *command-line-args*

If neither -e, -f, or --socket-repl are specified, then the first argument that is not parsed as a option is treated as a file if it exists, or as an expression otherwise.
Everything after that is bound to *command-line-args*.
```

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

The following namespaces are required by default and available through the
pre-defined aliases in the `user` namespace. You may use `require` + `:as`
and/or `:refer` on these namespaces. If not all vars are available, they are
enumerated explicitly.

- `clojure.string` aliased as `str`
- `clojure.set` aliased as `set`
- `clojure.edn` aliased as `edn`:
  - `read-string`
- `clojure.java.shell` aliased as `shell`
- `clojure.java.io` aliased as `io`:
  - `as-relative-path`, `as-url`, `copy`, `delete-file`, `file`, `input-stream`,
    `make-parents`, `output-stream`, `reader`, `resource`, `writer`
- `clojure.main`: `repl`
- [`clojure.core.async`](https://clojure.github.io/core.async/) aliased as
  `async`. The `alt` and `go` macros are not available but `alts!!` does work as
  it is a function.
- `clojure.stacktrace`
- `clojure.test`
- `clojure.pprint`: `pprint` (currently backed by [fipp](https://github.com/brandonbloom/fipp)'s  `fipp.edn/pprint`)
- [`clojure.tools.cli`](https://github.com/clojure/tools.cli) aliased as `tools.cli`
- [`clojure.data.csv`](https://github.com/clojure/data.csv) aliased as `csv`
- [`cheshire.core`](https://github.com/dakrone/cheshire) aliased as `json`

A selection of java classes are available, see `babashka/impl/classes.clj`.

Babashka supports `import`: `(import clojure.lang.ExceptionInfo)`.

Babashka supports a subset of the `ns` form where you may use `:require` and `:import`:

``` shellsession
(ns foo
  (:require [clojure.string :as str])
  (:import clojure.lang.ExceptionInfo))
```

For the unsupported parts of the ns form, you may use [reader
conditionals](#reader-conditionals) to maintain compatibility with JVM Clojure.

### Input and output flags

In one-liners the `*input*` value may come in handy. It contains the input read from stdin as EDN by default. If you want to read in text, use the `-i` flag, which binds `*input*` to a lazy seq of lines of text. If you want to read multiple EDN values, use the `-I` flag. The `-o` option prints the result as lines of text. The `-O` option prints the result as lines of EDN values.

The following table illustrates the combination of options for commands of the form

    echo "{{Input}}" | bb {{Input flags}} {{Output flags}} "*input*"

| Input          | Input flags | Output flag | `*input*`     | Output   |
|----------------|-------------|-------------|---------------|----------|
| `{:a 1}` <br> `{:a 2}` |             |             | `{:a 1}`      | `{:a 1}` |
| hello <br> bye | `-i`        |             | `("hello" "bye")` |  `("hello" "bye")` |
| hello <br> bye | `-i`        |  `-o`       | `("hello" "bye")` |  hello <br> bye  |
| `{:a 1}` <br> `{:a 2}` | `-I`        |        | `({:a 1} {:a 2})` |  `({:a 1} {:a 2})`   |
| `{:a 1}` <br> `{:a 2}` | `-I` |  `-O`      | `({:a 1} {:a 2})` |  `{:a 1}` <br> `{:a 2}`   |

When combined with the `--stream` option, the expression is executed for each value in the input:

``` clojure
$ echo '{:a 1} {:a 2}' | bb --stream '*input*'
{:a 1}
{:a 2}
```

### Current file path

The var `*file*` contains the full path of the file that is currently being
executed:

``` shellsession
$ cat example.clj
(prn *file*)

$ bb example.clj
"/Users/borkdude/example.clj"
```

### Command-line arguments

Command-line arguments can be retrieved using `*command-line-args*`.

### Additional namespaces

#### babashka.classpath

Contains the function `add-classpath` which can be used to add to the classpath
dynamically:

``` clojure
(require '[babashka.classpath :refer [add-classpath]]
         '[clojure.java.shell :refer [sh]])
(def medley-dep '{:deps {medley {:git/url "https://github.com/borkdude/medley"
                                 :sha "91adfb5da33f8d23f75f0894da1defe567a625c0"}}})
(def cp (:out (sh "clojure" "-Spath" "-Sdeps" (str medley-dep))))
(add-classpath cp)
(require '[medley.core :as m])
(m/index-by :id [{:id 1} {:id 2}]) ;;=> {1 {:id 1}, 2 {:id 2}}
```

#### babashka.wait

Contains the functions: `wait-for-port` and `wait-for-path`.

Usage of `wait-for-port`:

``` clojure
(wait/wait-for-port "localhost" 8080)
(wait/wait-for-port "localhost" 8080 {:timeout 1000 :pause 1000})
```

Waits for TCP connection to be available on host and port. Options map supports `:timeout` and `:pause`. If `:timeout` is provided and reached, `:default`'s value (if any) is returned. The `:pause` option determines the time waited between retries.

Usage of `wait-for-path`:

``` clojure
(wait/wait-for-path "/tmp/wait-path-test")
(wait/wait-for-path "/tmp/wait-path-test" {:timeout 1000 :pause 1000})
```

Waits for file path to be available. Options map supports `:default`, `:timeout`
and `:pause`. If `:timeout` is provided and reached, `:default`'s value (if any)
is returned. The `:pause` option determines the time waited between retries.

The namespace `babashka.wait` is aliased as `wait` in the `user` namespace.

#### babashka.signal

Contains the function `signal/pipe-signal-received?`. Usage:

``` clojure
(signal/pipe-signal-received?)
```

Returns true if `PIPE` signal was received. Example:

``` shellsession
$ bb '((fn [x] (println x) (when (not (signal/pipe-signal-received?)) (recur (inc x)))) 0)' | head -n2
1
2
```

The namespace `babashka.signal` is aliased as `signal` in the `user` namespace.

## Running a file

Scripts may be executed from a file using `-f` or `--file`:

``` shellsession
bb -f download_html.clj
```

Files can also be loaded inline using `load-file`:

``` shellsession
bb '(load-file "script.clj")'
```

Using `bb` with a shebang also works:

``` clojure
#!/usr/bin/env bb

(defn get-url [url]
  (println "Fetching url:" url)
  (let [{:keys [:exit :err :out]} (shell/sh "curl" "-sS" url)]
    (if (zero? exit) out
      (do (println "ERROR:" err)
          (System/exit 1)))))

(defn write-html [file html]
  (println "Writing file:" file)
  (spit file html))

(let [[url file] *command-line-args*]
  (when (or (empty? url) (empty? file))
    (println "Usage: <url> <file>")
    (System/exit 1))
  (write-html file (get-url url)))

(System/exit 0)
```

``` shellsession
$ ./download_html.clj
Usage: <url> <file>

$ ./download_html.clj https://www.clojure.org /tmp/clojure.org.html
Fetching url: https://www.clojure.org
Writing file: /tmp/clojure.org.html
```

If `/usr/bin/env` doesn't work for you, you can use the following workaround:

``` shellsession
$ cat script.clj
#!/bin/sh

#_(
   "exec" "bb" "$0" hello "$@"
   )

(prn *command-line-args*)

./script.clj 1 2 3
("hello" "1" "2" "3")
```

## Preloads

The environment variable `BABASHKA_PRELOADS` allows to define code that will be
available in all subsequent usages of babashka.

``` shellsession
BABASHKA_PRELOADS='(defn foo [x] (+ x 2))'
BABASHKA_PRELOADS=$BABASHKA_PRELOADS' (defn bar [x] (* x 2))'
export BABASHKA_PRELOADS
```

Note that you can concatenate multiple expressions. Now you can use these functions in babashka:

``` shellsession
$ bb '(-> (foo *input*) bar)' <<< 1
6
```

You can also preload an entire file using `load-file`:

``` shellsession
export BABASHKA_PRELOADS='(load-file "my_awesome_prelude.clj")'
```

Note that `*input*` is not available in preloads.

## Classpath

Babashka accepts a `--classpath` option that will be used to search for
namespaces and load them:

``` clojure
$ cat src/my/namespace.clj
(ns my.namespace)
(defn -main [& _args]
  (println "Hello from my namespace!"))

$ bb --classpath src --main my.namespace
Hello from my namespace!
```

Note that you can use the `clojure` tool to produce classpaths and download dependencies:

``` shellsession
$ cat deps.edn
{:deps
 {my_gist_script
  {:git/url "https://gist.github.com/borkdude/263b150607f3ce03630e114611a4ef42"
   :sha "cfc761d06dfb30bb77166b45d439fe8fe54a31b8"}}
 :aliases {:my-script {:main-opts ["-m" "my-gist-script"]}}}

$ CLASSPATH=$(clojure -Spath)
$ bb --classpath "$CLASSPATH" --main my-gist-script
Hello from gist script!
```

If there is no `--classpath` argument, the `BABASHKA_CLASSPATH` environment
variable will be used:

``` shellsession
$ export BABASHKA_CLASSPATH=$(clojure -Spath)
$ export BABASHKA_PRELOADS="(require '[my-gist-script])"
$ bb "(my-gist-script/-main)"
Hello from gist script!
```

### Deps.clj

The [`deps.clj`](https://github.com/borkdude/deps.clj/) script can be used to work with `deps.edn`-based projects:

``` shell
$ deps.clj -A:my-script -Scommand "bb -cp {{classpath}} {{main-opts}}"
Hello from gist script!
```

Create these aliases for brevity:

``` shell
$ alias bbk='deps.clj -Scommand "bb -cp {{classpath}} {{main-opts}}"'
$ alias babashka='rlwrap deps.clj -Scommand "bb -cp {{classpath}} {{main-opts}}"'
$ bbk -A:my-script
Hello from gist script!
$ babashka
Babashka v0.0.58 REPL.
Use :repl/quit or :repl/exit to quit the REPL.
Clojure rocks, Bash reaches.

user=> (require '[my-gist-script :as mgs])
nil
user=> (mgs/-main)
Hello from gist script!
nil
```

## Uberscript

The `--uberscript` option collects the expressions in
`BABASHKA_PRELOADS`, the command line expression or file, the main entrypoint
and all required namespaces from the classpath into a single file. This can be
convenient for debugging and deployment.

Given the `deps.edn` from above:

``` clojure
$ deps.clj -A:my-script -Scommand "bb -cp {{classpath}} {{main-opts}} --uberscript my-script.clj"

$ cat my-script.clj
(ns my-gist-script)
(defn -main [& args]
  (println "Hello from gist script!"))
(ns user (:require [my-gist-script]))
(apply my-gist-script/-main *command-line-args*)

$ bb my-script.clj
Hello from gist script!
```

## Parsing command line arguments

Babashka ships with `clojure.tools.cli`:

``` clojure
(require '[clojure.tools.cli :refer [parse-opts]])

(def cli-options
  ;; An option with a required argument
  [["-p" "--port PORT" "Port number"
    :default 80
    :parse-fn #(Integer/parseInt %)
    :validate [#(< 0 % 0x10000) "Must be a number between 0 and 65536"]]
   ["-h" "--help"]])

(:options (parse-opts *command-line-args* cli-options))
```

``` shellsession
$ bb script.clj
{:port 80}
$ bb script.clj -h
{:port 80, :help true}
```

## Reader conditionals

Babashka supports reader conditionals by taking either the `:bb` or `:clj`
branch, whichever comes first. NOTE: the `:clj` branch behavior was added in
version 0.0.71, before that version the `:clj` branch was ignored.

``` clojure
$ bb "#?(:bb :hello :clj :bye)"
:hello

$ bb "#?(:clj :bye :bb :hello)"
:bye

$ bb "[1 2 #?@(:bb [] :clj [1])]"
[1 2]
```

## Running tests

Babashka bundles `clojure.test`. To make CI scripts fail you can use a simple
runner like this:

``` shell
#!/usr/bin/env bash
bb -cp "src:test:resources" \
   -e "(require '[clojure.test :as t] '[borkdude.deps-test])
       (let [{:keys [:fail :error]} (t/run-tests 'borkdude.deps-test)]
         (System/exit (+ fail error)))"
```

## REPL

Babashka supports both a REPL and socket REPL. To start the REPL, type:

``` shell
$ bb --repl
```

To get history with up and down arrows, use `rlwrap`:

``` shell
$ rlwrap bb --repl
```

To start the socket REPL you can do this:

``` shellsession
$ bb --socket-repl 1666
Babashka socket REPL started at localhost:1666
```

Now you can connect with your favorite socket REPL client:

``` shellsession
$ rlwrap nc 127.0.0.1 1666
Babashka v0.0.14 REPL.
Use :repl/quit or :repl/exit to quit the REPL.
Clojure rocks, Bash reaches.

bb=> (+ 1 2 3)
6
bb=> :repl/quit
$
```

A socket REPL client for Emacs is
[inf-clojure](https://github.com/clojure-emacs/inf-clojure).

## Spawning and killing a process

Use the `java.lang.ProcessBuilder` class.

Example:

``` clojure
user=> (def ws (-> (ProcessBuilder. ["python" "-m" "SimpleHTTPServer" "1777"]) (.start)))
#'user/ws
user=> (wait/wait-for-port "localhost" 1777)
{:host "localhost", :port 1777, :took 2}
user=> (.destroy ws)
nil
```

Also see this [example](examples/process_builder.clj).

## Async

Apart from `future` and `pmap` for creating threads, you may use the `async`
namespace, which maps to `clojure.core.async`, for asynchronous scripting. The
following example shows how to get first available value from two different
processes:

``` clojure
bb '
(defn async-command [& args]
  (async/thread (apply shell/sh "bash" "-c" args)))

(-> (async/alts!! [(async-command "sleep 2 && echo process 1")
                   (async-command "sleep 1 && echo process 2")])
    first :out str/trim println)'
process 2
```

## Differences with Clojure

Babashka is implemented using the [Small Clojure
Interpreter](https://github.com/borkdude/sci). This means that a snippet or
script is not compiled to JVM bytecode, but executed form by form by a runtime
which implements a subset of Clojure. Babashka is compiled to a native binary
using [GraalVM](https://github.com/oracle/graal). It comes with a selection of
built-in namespaces and functions from Clojure and other useful libraries. The
data types (numbers, strings, persistent collections) are the
same. Multi-threading is supported (`pmap`, `future`).

Differences with Clojure:

- A subset of Java classes are supported.

- Only the `clojure.core`, `clojure.edn`, `clojue.java.io`,
  `clojure.java.shell`, `clojure.set`, `clojure.stacktrace`, `clojure.string`,
  `clojure.template`, `clojure.test` and `clojure.walk` namespaces are available
  from Clojure.

- Interpretation comes with overhead. Therefore tight loops are likely slower
  than in Clojure on the JVM.

- No support for unboxed types.

## External resources

### Tools and libraries

The following libraries are known to work with Babashka:

#### [deps.clj](https://github.com/borkdude/deps.clj)

A port of the [clojure](https://github.com/clojure/brew-install/) bash script to
Clojure / babashka.

#### [spartan.spec](https://github.com/borkdude/spartan.spec/)

An babashka-compatible implementation of `clojure.spec.alpha`.

#### [missing.test.assertions](https://github.com/borkdude/missing.test.assertions)

This library checks if no assertions have been made in a test:

``` shell
$ export BABASHKA_CLASSPATH=$(clojure -Spath -Sdeps '{:deps {borkdude/missing.test.assertions {:git/url "https://github.com/borkdude/missing.test.assertions" :sha "603cb01bee72fb17addacc53c34c85612684ad70"}}}')

$ lein bb "(require '[missing.test.assertions] '[clojure.test :as t]) (t/deftest foo) (t/run-tests)"

Testing user
WARNING: no assertions made in test foo

Ran 1 tests containing 0 assertions.
0 failures, 0 errors.
{:test 1, :pass 0, :fail 0, :error 0, :type :summary}
```

#### [medley](https://github.com/weavejester/medley/)

Requires `bb` >= v0.0.71. Latest coordinates checked with with bb:

``` clojure
{:git/url "https://github.com/weavejester" :sha "a4e5fb5383f5c0d83cb2d005181a35b76d8a136d"}
```

Example:

``` shell
$ export BABASHKA_CLASSPATH=$(clojure -Spath -Sdeps '{:deps {medley {:git/url "https://github.com/weavejester" :sha "a4e5fb5383f5c0d83cb2d005181a35b76d8a136d"}}}')

$ bb -e "(require '[medley.core :as m]) (m/index-by :id [{:id 1} {:id 2}])"
{1 {:id 1}, 2 {:id 2}}
```

#### [clj-http-lite](https://github.com/borkdude/clj-http-lite)

This fork does not depend on any other libraries. Example:

``` shell
$ export BABASHKA_CLASSPATH="$(clojure -Sdeps '{:deps {clj-http-lite {:git/url "https://github.com/borkdude/clj-http-lite" :sha "f44ebe45446f0f44f2b73761d102af3da6d0a13e"}}}' -Spath)"

$ bb "(require '[clj-http.lite.client :as client]) (:status (client/get \"https://www.clojure.org\"))"
200
```

#### [limit-break](https://github.com/technomancy/limit-break)

A debug REPL library.

Latest coordinates checked with with bb:

``` clojure
{:git/url "https://github.com/technomancy/limit-break" :sha "050fcfa0ea29fe3340927533a6fa6fffe23bfc2f" :deps/manifest :deps}
```

Example:

``` shell
$ export BABASHKA_CLASSPATH="$(clojure -Sdeps '{:deps {limit-break {:git/url "https://github.com/technomancy/limit-break" :sha "050fcfa0ea29fe3340927533a6fa6fffe23bfc2f" :deps/manifest :deps}}}' -Spath)"

$ bb "(require '[limit.break :as lb]) (let [x 1] (lb/break))"
Babashka v0.0.49 REPL.
Use :repl/quit or :repl/exit to quit the REPL.
Clojure rocks, Bash reaches.

break> x
1
```

#### [clojure-csv](https://github.com/davidsantiago/clojure-csv)

A library for reading and writing CSV files. Note that babashka already comes
with `clojure.data.csv`, but in case you need this other library, this is how
you can use it:

``` shell
export BABASHKA_CLASSPATH="$(clojure -Sdeps '{:deps {clojure-csv {:mvn/version "RELEASE"}}}' -Spath)"

./bb -e "
(require '[clojure-csv.core :as csv])
(csv/write-csv (csv/parse-csv \"a,b,c\n1,2,3\"))
"
```

#### [regal](https://github.com/lambdaisland/regal)

Requires `bb` >= v0.0.71. Latest coordinates checked with with bb:

``` clojure
{:git/url "https://github.com/lambdaisland/regal" :sha "8d300f8e15f43480801766b7762530b6d412c1e6"}
```

Example:

``` shell
$ export BABASHKA_CLASSPATH=$(clojure -Spath -Sdeps '{:deps {regal {:git/url "https://github.com/lambdaisland/regal" :sha "8d300f8e15f43480801766b7762530b6d412c1e6"}}}')

$ bb -e "(require '[lambdaisland.regal :as regal]) (regal/regex [:* \"ab\"])"
#"(?:\Qab\E)*"
```

#### [spartan.test](https://github.com/borkdude/spartan.test/)

A minimal test framework compatible with babashka. This library is deprecated
since babashka v0.0.68 which has `clojure.test` built-in.


### Blogs

- [Babashka: a quick example](https://juxt.pro/blog/posts/babashka.html) by Malcolm Sparks
- [Clojure Start Time in 2019](https://stuartsierra.com/2019/12/21/clojure-start-time-in-2019) by Stuart Sierra
- [Advent of Random
  Hacks](https://lambdaisland.com/blog/2019-12-19-advent-of-parens-19-advent-of-random-hacks)
  by Arne Brasseur
- [Clojure in the Shell](https://lambdaisland.com/blog/2019-12-05-advent-of-parens-5-clojure-in-the-shell) by Arne Brasseur
- [Clojure Tool](https://purelyfunctional.tv/issues/purelyfunctional-tv-newsletter-351-clojure-tool-babashka/) by Eric Normand

## [Developing Babashka](doc/dev.md)

## Related projects

- [planck](https://planck-repl.org/)
- [joker](https://github.com/candid82/joker)
- [closh](https://github.com/dundalek/closh)
- [lumo](https://github.com/anmonteiro/lumo)

## Gallery

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

### Delete a list of files returned by a Unix command

```
find . | grep conflict | bb -i '(doseq [f *input*] (.delete (io/file f)))'
```

### Calculate aggregate size of directory

``` clojure
#!/usr/bin/env bb

(as-> (io/file (or (first *command-line-args*) ".")) $
  (file-seq $)
  (map #(.length %) $)
  (reduce + $)
  (/ $ (* 1024 1024))
  (println (str (int $) "M")))
```

``` shellsession
$ dir-size
130M

$ dir-size ~/Dropbox/bin
233M
```


### Shuffle the lines of a file

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

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

### Fetch latest Github release tag

For converting JSON to EDN, see [jet](https://github.com/borkdude/jet).

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

### Generate deps.edn entry for a gitlib

``` clojure
#!/usr/bin/env bb

(require '[clojure.java.shell :refer [sh]]
         '[clojure.string :as str])

(let [[username project branch] *command-line-args*
      branch (or branch "master")
      url (str "https://github.com/" username "/" project)
      sha (-> (sh "git" "ls-remote" url branch)
              :out
              (str/split #"\s")
              first)]
  {:git/url url
   :sha sha})
```

``` shell
$ gitlib.clj nate fs
{:git/url "https://github.com/nate/fs", :sha "75b9fcd399ac37cb4f9752a4c7a6755f3fbbc000"}
$ clj -Sdeps "{:deps {fs $(gitlib.clj nate fs)}}" \
  -e "(require '[nate.fs :as fs]) (fs/creation-time \".\")"
#object[java.nio.file.attribute.FileTime 0x5c748168 "2019-07-05T14:06:26Z"]
```

### View download statistics from Clojars

Contributed by [@plexus](https://github.com/plexus).

``` shellsession
$ curl https://clojars.org/stats/all.edn |
bb -o '(for [[[group art] counts] *input*] (str (reduce + (vals counts))  " " group "/" art))' |
sort -rn |
less
14113842 clojure-complete/clojure-complete
9065525 clj-time/clj-time
8504122 cheshire/cheshire
...
```

### Portable tree command

See [examples/tree.clj](https://github.com/borkdude/babashka/blob/master/examples/tree.clj).

``` shellsession
$ clojure -Sdeps '{:deps {org.clojure/tools.cli {:mvn/version "0.4.2"}}}' examples/tree.clj src
src
└── babashka
    ├── impl
    │   ├── tools
    │   │   └── cli.clj
...

$ examples/tree.clj src
src
└── babashka
    ├── impl
    │   ├── tools
    │   │   └── cli.clj
...
```

### List outdated maven dependencies

See [examples/outdated.clj](https://github.com/borkdude/babashka/blob/master/examples/outdated.clj).
Inspired by an idea from [@seancorfield](https://github.com/seancorfield).

``` shellsession
$ cat /tmp/deps.edn
{:deps {cheshire {:mvn/version "5.8.1"}
        clj-http {:mvn/version "3.4.0"}}}

$ examples/outdated.clj /tmp/deps.edn
clj-http/clj-http can be upgraded from 3.4.0 to 3.10.0
cheshire/cheshire can be upgraded from 5.8.1 to 5.9.0
```

### Convert project.clj to deps.edn

Contributed by [@plexus](https://github.com/plexus).

``` shellsession
$ cat project.clj |
sed -e 's/#=//g' -e 's/~@//g' -e 's/~//g' |
bb '(let [{:keys [dependencies source-paths resource-paths]} (apply hash-map (drop 3 *input*))]
  {:paths (into source-paths resource-paths)
   :deps (into {} (for [[d v] dependencies] [d {:mvn/version v}]))}) ' |
jet --pretty > deps.edn
```

### Print current time in California

See [examples/pst.clj](https://github.com/borkdude/babashka/blob/master/examples/pst.clj)

### Tiny http server

See [examples/http_server.clj](https://github.com/borkdude/babashka/blob/master/examples/http_server.clj)

Original by [@souenzzo](https://gist.github.com/souenzzo/a959a4c5b8c0c90df76fe33bb7dfe201)

### Print random docstring

See [examples/random_doc.clj](https://github.com/borkdude/babashka/blob/master/examples/random_doc.clj)

``` shell
$ examples/random_doc.clj
-------------------------
clojure.core/ffirst
([x])
  Same as (first (first x))
```

## Thanks

- [adgoji](https://www.adgoji.com/) for financial support

## License

Copyright © 2019 Michiel Borkent

Distributed under the EPL License. See LICENSE.

This project contains code from:
- Clojure, which is licensed under the same EPL License.