flex-exec

flex-exec
=========

Call a child process with the ease of exec and safety of spawn

INFORMAION We don't like a DEPRECATED text printed in console. So, I clone
project and changed it.

DEPRECATED: If your version of node supports child_process.execFile, consider
using that instead, as that does everything this module does and more... the usage
is slightly different.

[http://nodejs.org/api/child_process.html#child_process_child_process_execfile_file_args_options_callback]
(http://nodejs.org/api/child_process.html#child_process_child_process_execfile_file_args_options_callback)

Why?
----

This module provides the best of both worlds of spawn and exec

It will callback with 2 strings containing stdout and stderr
(like child_process.exec), but will take an array of process arguments
(like child_process.spawn) to avoid any potentially harmful shell expansion.

Usage
-----

`` js
var exec = require('exec');
`

Example
-------

` js
var exec = require('exec');

exec(['ls', '-lha'], function(err, out, code) {
if (err instanceof Error)
throw err;
process.stderr.write(err);
process.stdout.write(out);
process.exit(code);
});
`

The example above will call ls -lha safely, by passing the arguments directly
to exec(2) without using an shell expansion/word splitting.

It returns a child_process.spawn object, and callbacks with any stdout,
stderr, and the exit status of the command. The above example will throw an
error if anything went wrong during the spawn, otherwise it will print the stdout,
stderr, and exit with the exit code of ls.

NOTE: If err is an instanceof Error, it means that child_process.spawn emitted
and error event, and err is set to that error object.

err and out are encoded asutf-8 strings by default

For backwards compatibility with child_process.exec, it is also possible
to pass a string to exec. The string will automatically be converted to
['/bin/sh', '-c', '{string}'], which will cause the string to be parsed on the
shell. Note that if you use this method, you are at risk of shell expansion,
word splitting, and other shell features that could be potentially unsafe.

` js
exec('cat foo | grep bar', function(err, out, code) {
if (err instanceof Error)
throw err;
process.stderr.write(err);
process.stdout.write(out);
process.exit(code);
});
`

Functions
---------

$3

- args: an array of arguments to execute
- opts: is additional options to pass to child_process.spawn

In addition to the child_process.spawn options, more options have been added to mimic the behavior
of child_process.exec

- opts.timeout: number of milliseconds to wait for the program to complete before sending it
SIGTERM. Note that by default, your program will wait indefinitely for the
spawned program to terminate. Upon sending the fatal signal, exec will return
with whatever stdout and stderr was produced.
- opts.killSignal: the signal to use when opts.timeout is used, defaults to SIGTERM
- opts.encoding: the encoding to use for stdout and stderr. NOTE: unlike child_process.exec, this defaults
to 'utf-8' if unset. Set to 'buffer'` to handle binary data.

Installation
------------

npm install exec

License
-------

MIT