[1]: http://example.com
[2]: https://github.com/mikeal/request
[3]: http://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options
[4]: http://nodejs.org/api/child_process.html#child_process_child_process_execfile_file_args_options_callback

Grep

This is a simple wrapper around grep(1). The module use child_process to create
grep processes and use streams and callbacks to communicate.

Install

Using npm:
``sh
$ npm install grep
`
From source:
`sh
$ git clone https://github.com/ladinu/node-grep.git
$ cd node-grep
$ npm link
`

Examples

Grep file /tmp/file for expression spurs:
`javascript
grep(['spurs', '/tmp/file'], function(err, stdout, stderr) {
if (err || stderr) {
console.log(err, stderr);
} else {
console.log(stdout);
}
});
`

Grep file /tmp/file for expression spurs:
`javascript
var search = grep(['spurs', '/tmp/file']);

search.pipe(process.stdout);

search.on('error', function(err) {
console.log(err);
});
`

Using [request][2], grep [example.com][1] for expression examples
`javascript
var req = require('request');
var search = grep('examples');

search.pipe(process.stdout);
req('http://example.com').pipe(search);
`

API

$3

This class wrap grep(1) using node's child_process module. When a callback is given
child_process.execFile() is used and returns a Grep object which is a destroyed stream.
When no callback, child_process.spawn() is used and returns a Grep object which is a
stream.


#### Event: 'error'

Process's stderr is emitted as error events.

#### Event: 'data'

Process's stdout is emitted as data events.

$3



* args The arguments given to grep(1) processes. By default args is concatinated
with an empty array and passed to grep(1) process. See options to change this
behaviour.

options Object* for Grep object. Note

buildArgs Function* that build arguments for grep(1) processes. By default this is
set to a function that concatinate given args to an empty array. So when you call
grep("some_pharse") the actual arguments given to grep(1) process is
[ 'some_phrase' ].

execOptions Object* that give options such as cwd to each grep(1) process. By
default this is an empty object. This is the same options object that you would use
when calling child_process.execFile() or child_process.spawn(). Because a callback
is given, child_process.execFile() is used. See node [documentation][4] for more
information.


callback Function* that is called when grep(1) process terminate
error Error*
stdout Buffer*
stderr Buffer*

* Returns a Grep object

$3

* args Same as grep([args], [options], callback)

* options Same as grep([args], [options], callback) except child_process.spawn()
is used. See node [documentation][3] for more infromation

* Returns a Grep object

$3

This will make options global when options is not given to grep([args], [options])
or grep([args], [options], callback)

* Returns: nothing

For example:
`javascript
// Set buildArgs so grep(1) will count line numbers.
// Set current working directory to '/var/log' and perform
// grep operations on file 'some.log'
//
// When you call grep("phrase"), a new grep(1) process will
// be created with arguments ['-n', 'phrase', 'some.log']

var fs = require('fs');
warningFile = fs.createWriteStream('./warnings.txt');
errorFile = fs.createWriteStream('./errors.txt');

grep.configure({
buildArgs: function(args) { return ['-n', args, 'some.log'] }
, execOptions: {cwd: '/var/log'}
});

var warning = grep('[+} Warning');
var errors = grep('[!] Error');

warning.pipe(warningFile);
errors.pipe(errorFile);


// Grep file '/tmp/foo.txt' for first occurance of 'bar'
// Note: global options set above do not apply because we
// are giving an an empty options object

var options = {};
var bar = grep(['-m', '1', 'bar', '/tmp/foo.txt'], options);
bar.pipe(process.stdout);
`

$3

Helper method to clear global settings. This basically set buildArgs to null and
execOptions` to an empty object.

License

Copyright (c) 2013 Ladinu Chandrasinghe

Permission is hereby granted, free of charge, to any person obtaining a copy of this
software and associated documentation files (the "Software"), to deal in the Software
without restriction, including without limitation the rights to use, copy, modify,
merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be included in all copies
or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
THE USE OR OTHER DEALINGS IN THE SOFTWARE.