Feature #2351
closed
system() hardlinked to /bin/sh
Description
=begin
I encountered this problem while using a feature of the very powerful zsh(ell).
In zsh one can use regular expressions in shell commands, like accessing files in
different locations with one command:
cat -la /mnt/server(1|2)/some/path/and/file_log
The default /bin/sh does not as it is a bash in most cases.
Example:
% irb
ENV['SHELL']
=> "/usr/bin/zsh"
system('cat /mnt/server(1|2|3)/file | sed, awk, etc.')
sh: Syntax error: "(" unexpected
=> false
I can update the ENV['SHELL'] to every setting I'd like, but system() will always refer to /bin/sh.
Thus my script will always fail as long as I do not circumvent this feature with something like:
system('/usr/bin/zsh -c "cat /mnt/server(1|2|3)/file | sed, awk, etc."')
I tested this with different ruby versions installed by different Linux distributions:
ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux] Ubuntu 9.04
ruby 1.8.7 (2008-08-11 patchlevel 72) [x86_64-linux] openSuSE 11.1
ruby 1.8.7 (2009-04-08 patchlevel 160) [i386-freebsd7]
ruby 1.8.5 (2006-08-25) [i386-linux] CentOS release 5.3 (Final)
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Updated by shyouhei (Shyouhei Urabe) over 14 years ago
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Moving this to the feature request tracker.
Kernel#system's invoking /bin/sh is not 1.8.7 specific.
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Updated by kosaki (Motohiro KOSAKI) over 14 years ago
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Hi
SUS says
The environment of the executed command shall be as if a child process were created using fork(), and the child process invoked
the sh utility using execl() as follows:execl(, "sh", "-c", command, (char *)0);
where is an unspecified pathname for the sh utility.
In other word, it doesn't refer SHELL environemnt. Now ruby does so too because it is easy understandable.
Moreover you can invoke zsh easily by you wrote or similar way.
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Updated by kosaki (Motohiro KOSAKI) over 14 years ago
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And if we accept this proposal, system() will lose user enviroment portability. e.g. csh has completely different syntax from /bin/sh. Thus, distributed ruby scripts will not be able to use system().
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Updated by meta (mathew murphy) over 14 years ago
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On Fri, Nov 26, 2010 at 08:18, Motohiro KOSAKI [email protected]wrote:
And if we accept this proposal, system() will lose user enviroment
portability. e.g. csh has completely different syntax from /bin/sh. Thus,
distributed ruby scripts will not be able to use system().
Surely anyone using system() to execute a shell script will be using a
shebang (#!) line to specify the shell the script is supposed to be executed
by?
If you don't, you're likely to discover that ksh is the standard POSIX
shell, not sh; and then there's the whole issue of bash vs ash vs sh.
mathew
On Fri, Nov 26, 2010 at 08:18, Motohiro KOSAKI <[email protected]> wrote:
And if we accept this proposal, system() will lose user enviroment portability. e.g. csh has completely different syntax from /bin/sh. Thus, distributed ruby scripts will not be able to use system().
mathew
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Updated by kosaki (Motohiro KOSAKI) over 14 years ago
=begin
2010/11/27 mathew [email protected]:
On Fri, Nov 26, 2010 at 08:18, Motohiro KOSAKI [email protected]
wrote:And if we accept this proposal, system() will lose user enviroment
portability. e.g. csh has completely different syntax from /bin/sh. Thus,
distributed ruby scripts will not be able to use system().Surely anyone using system() to execute a shell script will be using a
shebang (#!) line to specify the shell the script is supposed to be executed
by?
If you don't, you're likely to discover that ksh is the standard POSIX
shell, not sh; and then there's the whole issue of bash vs ash vs sh.
In practical world, peope who want distribute their own scripts are only using
ash subset. It works enough, I think.
=end
Updated by nahi (Hiroshi Nakamura) about 13 years ago
- Status changed from Open to Rejected
- Description updated (diff)
I close this as 'Rejected' since no update given long time.