Module: Shellwords

Defined in:
lib/shellwords.rb

Overview

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

The shellwords() function was originally a port of shellwords.pl, but modified to conform to POSIX / SUSv3 (IEEE Std 1003.1-2001).

Authors:

- Wakou Aoyama
- Akinori MUSHA <knu@iDaemons.org>

Contact:

- Akinori MUSHA <knu@iDaemons.org> (current maintainer)

Instance Method Summary collapse

Instance Method Details

#shellescape(str) ⇒ Object

Escapes a string so that it can be safely used in a Bourne shell command line.

Note that a resulted string should be used unquoted and is not intended for use in double quotes nor in single quotes.

open("| grep #{Shellwords.escape(pattern)} file") { |pipe|
  # ...
}

String#shellescape is a shorthand for this function.

open("| grep #{pattern.shellescape} file") { |pipe|
  # ...
}


72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
# File 'lib/shellwords.rb', line 72

def shellescape(str)
  # An empty argument will be skipped, so return empty quotes.
  return "''" if str.empty?

  str = str.dup

  # Process as a single byte sequence because not all shell
  # implementations are multibyte aware.
  str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n])/n, "\\\\\\1")

  # A LF cannot be escaped with a backslash because a backslash + LF
  # combo is regarded as line continuation and simply ignored.
  str.gsub!(/\n/, "'\n'")

  return str
end

#shelljoin(array) ⇒ Object

Builds a command line string from an argument list array joining all elements escaped for Bourne shell and separated by a space.

open('|' + Shellwords.join(['grep', pattern, *files])) { |pipe|
  # ...
}

Array#shelljoin is a shorthand for this function.

open('|' + ['grep', pattern, *files].shelljoin) { |pipe|
  # ...
}


109
110
111
# File 'lib/shellwords.rb', line 109

def shelljoin(array)
  array.map { |arg| shellescape(arg) }.join(' ')
end

#shellsplit(line) ⇒ Object Also known as: shellwords

Splits a string into an array of tokens in the same way the UNIX Bourne shell does.

argv = Shellwords.split('here are "two words"')
argv #=> ["here", "are", "two words"]

String#shellsplit is a shorthand for this function.

argv = 'here are "two words"'.shellsplit
argv #=> ["here", "are", "two words"]


32
33
34
35
36
37
38
39
40
41
42
43
44
45
# File 'lib/shellwords.rb', line 32

def shellsplit(line)
  words = []
  field = ''
  line.scan(/\G\s*(?>([^\s\\\'\"]+)|'([^\']*)'|"((?:[^\"\\]|\\.)*)"|(\\.?)|(\S))(\s|\z)?/m) do
    |word, sq, dq, esc, garbage, sep|
    raise ArgumentError, "Unmatched double quote: #{line.inspect}" if garbage
    field << (word || sq || (dq || esc).gsub(/\\(?=.)/, ''))
    if sep
      words << field
      field = ''
    end
  end
  words
end