# ShellJS - Unix shell commands for Node.js [![Build Status](https://secure.travis-ci.org/arturadib/shelljs.png)](http://travis-ci.org/arturadib/shelljs)
ShellJS is a portable **(Windows/Linux/OS X)** implementation of Unix shell commands on top of the Node.js API. You can use it to eliminate your shell script's dependency on Unix while still keeping its familiar and powerful commands. You can also install it globally so you can run it from outside Node projects - say goodbye to those gnarly Bash scripts!
The project is [unit-tested](http://travis-ci.org/arturadib/shelljs) and battled-tested in projects like:
+ [PDF.js](http://github.com/mozilla/pdf.js) - Firefox's next-gen PDF reader
if (exec('git commit -am "Auto-commit"').code !== 0) {
echo('Error: Git commit failed');
exit(1);
}
```
### CoffeeScript
```coffeescript
require 'shelljs/global'
if not which 'git'
echo 'Sorry, this script requires git'
exit 1
# Copy files to release dir
mkdir '-p', 'out/Release'
cp '-R', 'stuff/*', 'out/Release'
# Replace macros in each .js file
cd 'lib'
for file in ls '*.js'
sed '-i', 'BUILD_VERSION', 'v0.1.2', file
sed '-i', /.*REMOVE_THIS_LINE.*\n/, '', file
sed '-i', /.*REPLACE_LINE_WITH_MACRO.*\n/, cat 'macro.js', file
cd '..'
# Run external tool synchronously
if (exec 'git commit -am "Auto-commit"').code != 0
echo 'Error: Git commit failed'
exit 1
```
## Global vs. Local
The example above uses the convenience script `shelljs/global` to reduce verbosity. If polluting your global namespace is not desirable, simply require `shelljs`.
Example:
```javascript
var shell = require('shelljs');
shell.echo('hello world');
```
## Make tool
A convenience script `shelljs/make` is also provided to mimic the behavior of a Unix Makefile. In this case all shell objects are global, and command line arguments will cause the script to execute only the corresponding function in the global `target` object. To avoid redundant calls, target functions are executed only once per script.
Example (CoffeeScript):
```coffeescript
require 'shelljs/make'
target.all = ->
target.bundle()
target.docs()
target.bundle = ->
cd __dirname
mkdir 'build'
cd 'lib'
(cat '*.js').to '../build/output.js'
target.docs = ->
cd __dirname
mkdir 'docs'
cd 'lib'
for file in ls '*.js'
text = grep '//@', file # extract special comments
text.replace '//@', '' # remove comment tags
text.to 'docs/my_docs.md'
```
To run the target `all`, call the above script without arguments: `$ node make`. To run the target `docs`: `$ node make docs`, and so on.
<!--
DO NOT MODIFY BEYOND THIS POINT - IT'S AUTOMATICALLY GENERATED
-->
## Command reference
All commands run synchronously, unless otherwise stated.
### cd('dir')
Changes to directory `dir` for the duration of the script
Prints string to stdout, and returns string with additional utility methods
like `.to()`.
### pushd([options,] [dir | '-N' | '+N'])
Available options:
+ `-n`: Suppresses the normal change of directory when adding directories to the stack, so that only the stack is manipulated.
Arguments:
+ `dir`: Makes the current working directory be the top of the stack, and then executes the equivalent of `cd dir`.
+ `+N`: Brings the Nth directory (counting from the left of the list printed by dirs, starting with zero) to the top of the list by rotating the stack.
+ `-N`: Brings the Nth directory (counting from the right of the list printed by dirs, starting with zero) to the top of the list by rotating the stack.
Examples:
```javascript
// process.cwd() === '/usr'
pushd('/etc'); // Returns /etc /usr
pushd('+1'); // Returns /usr /etc
```
Save the current directory on the top of the directory stack and then cd to `dir`. With no arguments, pushd exchanges the top two directories. Returns an array of paths in the stack.
### popd([options,] ['-N' | '+N'])
Available options:
+ `-n`: Suppresses the normal change of directory when removing directories from the stack, so that only the stack is manipulated.
Arguments:
+ `+N`: Removes the Nth directory (counting from the left of the list printed by dirs), starting with zero.
+ `-N`: Removes the Nth directory (counting from the right of the list printed by dirs), starting with zero.
Examples:
```javascript
echo(process.cwd()); // '/usr'
pushd('/etc'); // '/etc /usr'
echo(process.cwd()); // '/etc'
popd(); // '/usr'
echo(process.cwd()); // '/usr'
```
When no arguments are given, popd removes the top directory from the stack and performs a cd to the new top directory. The elements are numbered from 0 starting at the first directory listed with dirs; i.e., popd is equivalent to popd +0. Returns an array of paths in the stack.