Last Modified
2017-10-08 18:11:11 -0500


Manipulates strings like the UNIX Bourne shell

This module manipulates strings according to the word parsing rules of the UNIX Bourne shell.

The shellwords() function was originally a port of, but modified to conform to the Shell & Utilities volume of the IEEE Std 1003.1-2008, 2016 Edition [1].


You can use Shellwords to parse a string into a Bourne shell friendly Array.

require 'shellwords'

argv = Shellwords.split('three blind "mice"')
argv #=> ["three", "blind", "mice"]

Once you've required Shellwords, you can use the split alias String#shellsplit.

argv = "see how they run".shellsplit
argv #=> ["see", "how", "they", "run"]

Be careful you don't leave a quote unmatched.

argv = "they all ran after the farmer's wife".shellsplit
     #=> ArgumentError: Unmatched double quote: ...

In this case, you might want to use Shellwords.escape, or its alias String#shellescape.

This method will escape the String for you to safely use with a Bourne shell.

argv = Shellwords.escape("special's.txt")
argv #=> "special\\'s.txt"
system("cat " + argv)

Shellwords also comes with a core extension for Array, Array#shelljoin.

argv = %w{ls -lta lib}

You can use this method to create an escaped string out of an array of tokens separated by a space. In this example we used the literal shortcut for




1: IEEE Std 1003.1-2008, 2016 Edition, the Shell & Utilities volume