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https://github.com/kumarshantanu/lein-exec

Leiningen plugin for executing Clojure scripts
https://github.com/kumarshantanu/lein-exec

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Leiningen plugin for executing Clojure scripts

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# lein-exec



Leiningen plugin to execute Clojure scripts



## Installation



### Lein 2 users



The recommended way is to install as a global plugin in `~/.lein/profiles.clj`:



```clojure

{:user {:plugins [[lein-exec "0.3.7"]]}}

```



You may also install as a project plugin in `project.clj`:



```clojure

:plugins [[lein-exec "0.3.7"]]

```



### Lein 1.x users



Either install as a plugin:



```shell

$ lein plugin install lein-exec "0.1"

```



Or, include as a dev-dependency:



```clojure

:dev-dependencies [[lein-exec "0.1"]]

```



## Usage



### Lein 2 users



This blog post covers lein-exec with examples:



[Scripting Clojure with Leiningen 2](http://charsequence.blogspot.in/2012/04/scripting-clojure-with-leiningen-2.html)



#### Synopsis



```

lein exec [-p]

lein exec -e[p] 

lein exec [-p]  [args]

```



When invoked without args it reads S-expressions from STDIN and evaluates them.

When only option `-p` is specified, it evaluates STDIN in project context.



```

-e  evaluates the following string as an S-expression

-ep evaluates the following string as an S-expression in project (w/classpath)

-p  indicates the script should be evaluated in project (with classpath)

```



#### Examples



```shell

cat foo.clj | lein exec

lein exec -e '(println "foo" (+ 20 30))'

lein exec -ep "(use 'foo.bar) (pprint (map baz (range 200)))"

lein exec -p script/run-server.clj -p 8088

lein exec ~/common/delete-logs.clj

```



Optional args after script-path are bound to `clojure.core/*command-line-args*`



#### Getting dependencies from within script



Thanks to the *pomegranate* library in Leiningen, lein-exec exposes an API to

specify dependencies that can be added dynamically to the CLASSPATH:



```clojure

(use '[leiningen.exec :only (deps)])

(deps '[[ring/ring-core "1.0.0"]

        [ring/ring-jetty-adapter "1.0.0"]])

(deps '[[foo/bar "1.2.3"]]

      :repositories {"myrepo" "http://mycorp.com/repositories/"})

```



This downloads dependencies from Maven Central and Clojars if required, and

uses the local repo on subsequent runs.



#### Executable scripts



*This may be applicable to Unix-like systems only.*



To run executable Clojure script files, you need to download the

[lein-exec](https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec) and

[lein-exec-p](https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec-p)

scripts, make them executable, and put them in PATH. After downloading the

scripts, you may also need to edit them in order to specify the correct name

for the Leiningen executable.



```shell

$ wget https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec

$ wget https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec-p

$ chmod a+x lein-exec lein-exec-p

$ mv lein-exec lein-exec-p ~/bin  # assuming ~/bin is in PATH

```



Executable Clojure script files that need not run *only* in project-scope

should have the following on the first line (shebang):



```shell

#!/usr/bin/env lein-exec

```

or,



```shell

#!/bin/bash lein-exec

```



Executable Clojure script files that are supposed to run *only* in project-scope

should have the following on the first line (shebang):



```shell

#!/usr/bin/env lein-exec-p

```



or,



```shell

#!/bin/bash lein-exec-p

```



#### Windows users



Windows users may not have the shebang header goodness, but they can use the

provided scripts (URLs below) as a convenience:



* [lein-exec.bat](https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec.bat)

* [lein-exec-p.bat](https://raw.github.com/kumarshantanu/lein-exec/master/lein-exec-p.bat)



### Lein 1.x users



You can execute scripts as follows in a project:



```shell

$ lein exec scripts/foobar.clj              # mention script path

$ lein exec scripts/run-server.clj -p 4000  # with arguments

```



The script would have project dependencies and source packages on CLASSPATH.



## Writing code to eval with lein-exec



It needs to be written as if would be eval'ed (rather than compiled) - example below:



```clojure

(require '[clojure.string :as str]

         '[clojure.pprint :as ppr]

         '[com.example.foo :as foo])



(defn baz

  [y]

  (let [x (str/join y (foo/quux :bla-bla))]

    (ppr/pprint [x foo/nemesis])))



(foo/bar :some-stuff)



(do

  (println *command-line-args*)  ; command-line args as a list

  (foo/bar :some-stuff)

  (baz ", "))

```



## Execute an ns having `-main` using lein-exec



Append the following to the namespace having `-main` fn:



```clojure

(try (require 'leiningen.exec)

     (when @(ns-resolve 'leiningen.exec '*running?*)

       (apply -main (rest *command-line-args*)))

     (catch java.io.FileNotFoundException e))

```



_Note:_ This works only on lein-exec 0.3.4 and later.



## Getting in touch



On Twitter: [@kumarshantanu](http://twitter.com/kumarshantanu)



On Leiningen mailing list: [http://groups.google.com/group/leiningen](http://groups.google.com/group/leiningen)



## Contributors



* https://github.com/edvorg (Edward Knyshov)

* https://github.com/jeroenvandijk (Jeroen van Dijk)

* https://github.com/geriatric

* https://github.com/hikoz

* https://github.com/mcandre (Andrew Pennebaker)

* https://github.com/mneilsen (Mike Neilsen )

* https://github.com/kbaribeau (Kevin Baribeau )

* https://github.com/sashton (Steve Ashton)



## License



Copyright (C) 2011-2017 Shantanu Kumar and contributors



Distributed under the Eclipse Public License, the same as Clojure.