module Shellwords
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 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} 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¶ ↑
Public Class Methods
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
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
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
Private Instance Methods
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
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
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