# Shellescape

**URL:** <https://www.ruby-forum.com/t/shellescape/114226>\
**Category:** Development\
**Created:** [September 10, 2007, 8:10am UTC](https://www.ruby-forum.com/t/shellescape/114226 "2007-09-10T08:10:59Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Akinori\_MUSHA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/b782af/32.png) [@Akinori\_MUSHA](https://www.ruby-forum.com/u/Akinori_MUSHA)\
**Post date:** [September 10, 2007, 8:10am UTC](https://www.ruby-forum.com/t/shellescape/114226/1 "2007-09-10T08:10:59Z")

</div>

　shellwords.rb に shellescape() ç­‰ã‚’è¿½åŠ ã—ã‚ˆã†ã¨æ€ã„ã¾ã™ã€‚

　理由としては、 system(), open(“|…”), IO.popen() 等でコマンド  
ラインを記述する際、メタ文字等をエスケープする適当な関数が標準で  
提供されていないためです。

　仕様としては、Bourneシェルに渡すことを想定し、安全でない文字を  
バックスラッシュ()でエスケープします。文字列はシングルバイト列  
として扱います。理由は以下の通りです。

- shellwords はそもそもBourneシェル(POSIX)の文法に則った処理を行う  
関数を提供するライブラリである。

- (Plan9の) rc 等を含め多くのシェルで使えるのが望ましいという声も  
[ruby-list:30049] 等で出た。しかし、Bourneシェルと rc では引用符  
(')のエスケープの仕方に互換性がなく、 Windows の cmd.exe も変数  
展開や引用符の扱いの差異が大きく、ひとつで全対応するエスケープ  
方法がない。

- 引用符(‘)で括る方式だと、感嘆符(!)の扱いの差異のため (t)csh で  
使えなくなってしまう。また、マルチバイト文字の中に引用符(’)が  
ã‚ã£ãŸå ´åˆã€ãƒžãƒ«ãƒãƒã‚¤ãƒˆå¯¾å¿œã®ã‚·ã‚§ãƒ«ã§ ‘…’'‘…’ が誤解釈  
される可能性が高い。

- 二重引用符(")で括る方式だと、バックスラッシュ()の扱いの差異の  
ため (t)csh で使えなくなってしまう。

　パッチを添付しました。以下がサマリーです。

- Shellwords.shellescape ã‚’è¿½åŠ :  
Bourneシェルに解釈される可能性のある文字をエスケープして返す  
(仕様は実装およびコメントを参照のこと)

- Shellwords.shelljoin ã‚’è¿½åŠ :  
与えられた引数列から、Bourneシェルコマンドライン文字列を生成  
して返す (shellescape を利用)

- Shellwords.shellwords の別名 shellsplit を定義

- 利用の便のため String ã‚„ Array にインスタンスメソッドを追åŠ

　cmd.exe ã‚„ rc ã®å¯¾å¿œã«ã¤ã„ã¦ã¯ã€å°†æ¥çš„ã«ã‚ªãƒ—ã‚·ãƒ§ãƒ³å¼•æ•°ã‚’è¿½åŠ ã—ã€  
プラットフォームごとに妥当なデフォルト値を設定することで対応でき  
ればと思います。

–  
/  
/\_\_ \_\_ [Akinori.org](http://Akinori.org) / [MUSHA.org](http://MUSHA.org)  
/ ) ) ) ) / [FreeBSD.org](http://FreeBSD.org) / [Ruby-lang.org](http://Ruby-lang.org)  
Akinori MUSHA aka / (\_ / ( (\_\_( @ [iDaemons.org](http://iDaemons.org) / and.or.jp

“Different eyes see different things,  
Different hearts beat on different strings –  
But there are times for you and me when all such things agree”

# Index: shellwords.rb

— shellwords.rb (revision 13420)  
+++ shellwords.rb (working copy)  
@@ -1,29 +1,31 @@

# 

-# shellwords.rb: Split text into an array of tokens a la UNIX shell  
+# shellwords.rb: Manipulates strings a la UNIX Bourne shell

# 

# 

-# This module is originally a port of shellwords.pl, but modified to  
-# conform to POSIX / SUSv3 (IEEE Std 1003.1-2001).  
+# This module manipulates strings according to the word parsing rules  
+# of the UNIX Bourne shell.

# 

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

# 

-# require ‘shellwords’  
-# words = Shellwords.shellwords(line)  
-#  
-# or  
-#  
-# require ‘shellwords’  
-# include Shellwords  
-# words = shellwords(line)  
+# Authors:  
+# - Wakou Aoyama  
+# - Akinori MUSHA [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

# 

module Shellwords

# 

- 
# Split text into an array of tokens in the same way the UNIX Bourne
- 
# shell does.

- 
# Splits a string into an array of tokens in the same way the UNIX
- 
# Bourne shell does.
- 
# 
- 
# argv = Shellwords.shellwords(‘here are “two words”’)
- 
# argv #=\> [“here”, “are”, “two words”]

# 

- 
# See the +Shellwords+ module documentation for an example.

- 
# +String#shellwords+ is a shorthand for this function.
- 
# 
- 
# argv = ‘here are “two words”’.shellwords
- 
# argv #=\> [“here”, “are”, “two words”]

# 
def shellwords(line)  
words = []  
@@ -39,6 +41,98 @@  
end  
words  
end
- alias shellsplit shellwords
- 
- 
# 
- 
# 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.shellescape(pattern)} file”) { |pipe|
- 
# # …
- 
# }
- 
# 
- 
# +String#shellescape+ is a shorthand for this function.
- 
# 
- 
# open(“| grep #{pattern.shellescape} file”) { |pipe|
- 
# # …
- 
# }
- 
# 
- 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
- 
- 
# 
- 
# Builds a command line string from an argument list +array+ joining
- 
# all elements escaped for Bourne shell and separated by a space.
- 
# 
- 
# open(‘|’ + Shellwords.shelljoin([‘grep’, pattern, \*files])) {

|pipe|

- 
# # …
- 
# }
- 
# 
- 
# +Array#shelljoin+ is a shorthand for this function.
- 
# 
- 
# open(‘|’ + [‘grep’, pattern, \*files].shelljoin) { |pipe|
- 
# # …
- 
# }
- 
# 
- def shelljoin(array)
- array.map { |arg| shellescape(arg) }.join(’ ')
- end
- 
- module\_function :shellwords, :shellsplit, :shellescape, :shelljoin  
+end
- 

+class String

- 
# 
- 
# call-seq:
- 
# str.shellwords =\> array
- 
# 
- 
# Splits +str+ into an array of tokens in the same way the UNIX
- 
# Bourne shell does. See +Shellwords::shellwords+ for details.
- 
# 
- def shellwords
- Shellwords.shellwords(self)
- end
- alias shellsplit shellwords

- module\_function :shellwords

- 
# 
- 
# call-seq:
- 
# str.shellescape =\> string
- 
# 
- 
# Escapes +str+ so that it can be safely used in a Bourne shell
- 
# command line. See +Shellwords::shellescape+ for details.
- 
# 
- def shellescape
- Shellwords.shellescape(self)
- end  
+end
- 

+class Array

- 
# 
- 
# call-seq:
- 
# array.shelljoin =\> string
- 
# 
- 
# Builds a command line string from an argument list +array+ joining
- 
# all elements escaped for Bourne shell and separated by a space.
- 
# See +Shellwords::shelljoin+ for details.
- 
# 
- def shelljoin
- Shellwords.shelljoin(self)
- end  
end

---

<div class="post-metadata">

**Author:** ![Akinori\_MUSHA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/b782af/32.png) [@Akinori\_MUSHA](https://www.ruby-forum.com/u/Akinori_MUSHA)\
**Post date:** [September 10, 2007, 9:03am UTC](https://www.ruby-forum.com/t/shellescape/114226/2 "2007-09-10T09:03:08Z")

</div>

e$B$J$+$@$G$9!#e(B

At Mon, 10 Sep 2007 15:10:13 +0900,  
Akinori MUSHA wrote in [ruby-dev:31768]:

> - Shellwords.shellescape e$B$rDI2Ce(B:  
> Bournee$B%7%’%k$K2r\<a$5$l$k2DG=@-$N$"$kJ8;z$r%(%9%1!\<%W$7$FJV$9e(B  
> (e$B;EMM$O\<BAu$\*$h$S%3%a%s%H$r;2\>H$N$3$He(B)
> 
> - Shellwords.shelljoin e$B$rDI2Ce(B:  
> e$BM?$($i$l$?0z?tNs$+$i!"e(BBournee$B%7%’%k%3%^%s%I%i%$%sJ8;zNs$r@8@.e(B  
> e$B$7$FJV$9e(B (shellescape e$B$rMxMQe(B)
> 
> - Shellwords.shellwords e$B$NJLL\>e(B shellsplit e$B$rDj5Ae(B

e$B%b%8%e!\<%k4X?t$K4X$9$k8B$j!"e(Bshelle$B$H$$$&e(Bprefixe$B$O$J$/$F$b$$$$$s$8$ce(B  
e$B$J$$$+$H;W$&$N$G$9$,!"e(BShellwords.escapee$B$de(BShellwords.join,  
Shellwords.splite$B$J$I$G$O$^$:$$$G$7$g$&$+!#e(B

---

<div class="post-metadata">

**Author:** ![Akinori\_MUSHA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/b782af/32.png) [@Akinori\_MUSHA](https://www.ruby-forum.com/u/Akinori_MUSHA)\
**Post date:** [September 10, 2007, 9:14am UTC](https://www.ruby-forum.com/t/shellescape/114226/3 "2007-09-10T09:14:08Z")

</div>

At Mon, 10 Sep 2007 16:01:47 +0900,  
Nobuyoshi N. wrote:

> > - Shellwords.shellwords の別名 shellsplit を定義
> 
> モジュール関数に関する限り、shellというprefixはなくてもいいんじゃ  
> ないかと思うのですが、Shellwords.escapeやShellwords.join,  
> Shellwords.splitなどではまずいでしょうか。

　私もそう思いました。しかし、現行のサンプルで include Shellwords  
する用例が載っているため、それを踏襲したコードが名前空間の汚染で  
動かなくなる可能性があります。(特に split)

　included() を定義して長い名前の方だけ落とすという手段はあるかも  
しれませんが…。

–  
/  
/\_\_ \_\_ [Akinori.org](http://Akinori.org) / [MUSHA.org](http://MUSHA.org)  
/ ) ) ) ) / [FreeBSD.org](http://FreeBSD.org) / [Ruby-lang.org](http://Ruby-lang.org)  
Akinori MUSHA aka / (\_ / ( (\_\_( @ [iDaemons.org](http://iDaemons.org) / and.or.jp

“Different eyes see different things,  
Different hearts beat on different strings –  
But there are times for you and me when all such things agree”

---

<div class="post-metadata">

**Author:** ![Akinori\_MUSHA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/b782af/32.png) [@Akinori\_MUSHA](https://www.ruby-forum.com/u/Akinori_MUSHA)\
**Post date:** [September 10, 2007, 11:30am UTC](https://www.ruby-forum.com/t/shellescape/114226/4 "2007-09-10T11:30:23Z")

</div>

At Mon, 10 Sep 2007 17:29:08 +0900,  
Nobuyoshi N. wrote:

> > 　included() を定義して長い名前の方だけ落とすという手段はあるかも  
> > しれませんが…。
> 
> インスタンスメソッドは長いものだけでいいと思います。特異メソッド  
> の方だけaliasすればいいのでは。

　そうか。include で降りてくるのはインスタンスメソッドの方だ。  
採用します。

> さすがにwordsは単独では意味不明なのでいらないと思います。

　メソッド名としての shellwords() はいまいちですよね。  
shellsplit を本名にして shellwords ã¯åˆ¥åã«æ ¼ä¸‹ã’ã™ã‚‹ã‹ã€‚

–  
/  
/\_\_ \_\_ [Akinori.org](http://Akinori.org) / [MUSHA.org](http://MUSHA.org)  
/ ) ) ) ) / [FreeBSD.org](http://FreeBSD.org) / [Ruby-lang.org](http://Ruby-lang.org)  
Akinori MUSHA aka / (\_ / ( (\_\_( @ [iDaemons.org](http://iDaemons.org) / and.or.jp

“Different eyes see different things,  
Different hearts beat on different strings –  
But there are times for you and me when all such things agree”

---

<div class="post-metadata">

**Author:** ![Akinori\_MUSHA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/b782af/32.png) [@Akinori\_MUSHA](https://www.ruby-forum.com/u/Akinori_MUSHA)\
**Post date:** [September 10, 2007, 10:30am UTC](https://www.ruby-forum.com/t/shellescape/114226/5 "2007-09-10T10:30:17Z")

</div>

e$B$J$+$@$G$9!#e(B

At Mon, 10 Sep 2007 16:12:58 +0900,  
Akinori MUSHA wrote in [ruby-dev:31770]:

> > e$B%b%8%e!\<%k4X?t$K4X$9$k8B$j!"e(Bshelle$B$H$$$&e(Bprefixe$B$O$J$/$F$b$$$$$s$8$ce(B  
> > e$B$J$$$+$H;W$&$N$G$9$,!"e(BShellwords.escapee$B$de(BShellwords.join,  
> > Shellwords.splite$B$J$I$G$O$^$:$$$G$7$g$&$+!#e(B
> 
> e$B!!;d$b$=$&;W$$$^$7$?!#$7$+$7!“8=9T$N%5%s%W%k$Ge(B include Shellwords  
> e$B$9$kMQNc$,:$C$F$$$k$?$a!”$=$l$rF’=1$7$?%3!\<%I$,L\>A06u4V$N1x@w$Ge(B  
> e$BF0$+$J$/$J$k2DG=@-$,$"$j$^$9!#e(B(e$BFC$Ke(B split)
> 
> e$B!!e(Bincluded() e$B$rDj5A$7$FD9$$L\>A0$NJ}$@$1Mn$H$9$H$$$&\<jCJ$O$"$k$+$be(B  
> e$B$7$l$^$;$s$,!D!#e(B

e$B%$%s%9%?%s%9%a%=%C%I$OD9$$$b$N$@$1$G$$$$$H;W$$$^$9!#FC0[%a%=%C%Ie(B  
e$B$NJ}$@$1e(Baliase$B$9$l$P$$$$$N$G$O!#e(B

module Shellwords  
module\_function :shellwords, :shellsplit, :shellescape, :shelljoin

```
class << self
  alias split shellsplit
  alias escape shellescape
  alias join shelljoin
end

```

end

e$B$5$9$,$Ke(Bwordse$B$OC1FH$G$O0UL#ITL@$J$N$G$$$i$J$$$H;W$$$^$9!#e(B