Module: Shellwords
Relationships & Source Files | |
Defined in: | lib/shellwords.rb |
Overview
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 shellwords.pl, but modified to conform to POSIX / SUSv3 (IEEE Std 1003.1-2001 [1]).
Usage
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 .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}
system(argv.shelljoin)
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 Array.new
.
Authors
-
Wakou Aoyama
-
Akinori MUSHA <knu@iDaemons.org>
Contact
-
Akinori MUSHA <knu@iDaemons.org> (current maintainer)
Resources
Class Method Summary
-
.escape(str)
Alias for .shellescape.
-
.join(array)
Alias for .shelljoin.
-
.split(line)
Alias for .shellsplit.
-
.shellescape(str)
(also: .escape)
mod_func
Escapes a string so that it can be safely used in a Bourne shell command line.
-
.shelljoin(array)
(also: .join)
mod_func
Builds a command line string from an argument list,
array
. -
.shellsplit(line)
(also: #shellwords, .split)
mod_func
Splits a string into an array of tokens in the same way the UNIX Bourne shell does.
-
.shellwords(line)
mod_func
Alias for #shellsplit.
Class Method Details
.escape(str)
Alias for .shellescape.
# File 'lib/shellwords.rb', line 154
alias escape shellescape
.join(array)
Alias for .shelljoin.
# File 'lib/shellwords.rb', line 184
alias join shelljoin
.shellescape(str) (mod_func) Also known as: .escape
Escapes a string so that it can be safely used in a Bourne shell command line. str
can be a non-string object that responds to to_s
.
Note that a resulted string should be used unquoted and is not intended for use in double quotes nor in single quotes.
argv = Shellwords.escape("It's better to give than to receive")
argv #=> "It\\'s\\ better\\ to\\ give\\ than\\ to\\ receive"
String#shellescape is a shorthand for this function.
argv = "It's better to give than to receive".shellescape
argv #=> "It\\'s\\ better\\ to\\ give\\ than\\ to\\ receive"
# Search files in lib for method definitions
pattern = "^[ \t]*def "
open("| grep -Ern #{pattern.shellescape} lib") { |grep|
grep.each_line { |line|
file, lineno, matched_line = line.split(':', 3)
# ...
}
}
It is the caller's responsibility to encode the string in the right encoding for the shell environment where this string is used.
Multibyte characters are treated as multibyte characters, not as bytes.
Returns an empty quoted ::String if str
has a length of zero.
# File 'lib/shellwords.rb', line 131
def shellescape(str) str = str.to_s # An empty argument will be skipped, so return empty quotes. return "''".dup if str.empty? str = str.dup # Treat multibyte characters as is. It is the caller's responsibility # to encode the string in the right encoding for the shell # environment. str.gsub!(/([^A-Za-z0-9_\-.,:\/@\n])/, "\\\\\\1") # A LF cannot be escaped with a backslash because a backslash + LF # combo is regarded as a line continuation and simply ignored. str.gsub!(/\n/, "'\n'") return str end
.shelljoin(array) (mod_func) Also known as: .join
Builds a command line string from an argument list, array
.
All elements are joined into a single string with fields separated by a space, where each element is escaped for the Bourne shell and stringified using to_s
.
ary = ["There's", "a", "time", "and", "place", "for", "everything"]
argv = Shellwords.join(ary)
argv #=> "There\\'s a time and place for everything"
Array#shelljoin is a shortcut for this function.
ary = ["Don't", "rock", "the", "boat"]
argv = ary.shelljoin
argv #=> "Don\\'t rock the boat"
You can also mix non-string objects in the elements as allowed in Array#join
.
output = `#{['ps', '-p', $$].shelljoin}`
# File 'lib/shellwords.rb', line 177
def shelljoin(array) array.map { |arg| shellescape(arg) }.join(' ') end
.shellsplit(line) (mod_func) Also known as: #shellwords, .split
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"]
Note, however, that this is not a command line parser. Shell metacharacters except for the single and double quotes and backslash are not treated as such.
argv = Shellwords.split('ruby my_prog.rb | less')
argv #=> ["ruby", "my_prog.rb", "|", "less"]
String#shellsplit is a shortcut for this function.
argv = 'here are "two words"'.shellsplit
argv #=> ["here", "are", "two words"]
# File 'lib/shellwords.rb', line 78
def shellsplit(line) words = [] field = String.new 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(/\\(.)/, '\\1')) if sep words << field field = String.new end end words end
.shellwords(line) (mod_func)
Alias for #shellsplit.
# File 'lib/shellwords.rb', line 93
alias shellwords shellsplit
.split(line)
Alias for .shellsplit.
# File 'lib/shellwords.rb', line 98
alias split shellsplit