This is the mail archive of the
mailing list for the Cygwin project.
Re: syntax for Cygwin bash invoking Win apps
- From: "Ziser, Jesse" <xezlec at yahoo dot com>
- To: cygwin at cygwin dot com
- Date: Wed, 9 Sep 2009 08:27:21 -0700 (PDT)
- Subject: Re: syntax for Cygwin bash invoking Win apps
>On 09/08/2009 11:30 PM, Ziser, Jesse wrote:
>> Hello list,
>> When I type a command in bash to invoke a Windows application (like
>> cmd.exe, for example), I can't seem to find a pattern in the Windows command
>> line that actually gets executed. Ordinary bash syntax does not seem to
>> apply in general when the command is a Windows app, but rather, sometimes
>> special characters are interpreted in a bash-like way, and sometimes not.
>> So, I'm wondering what determines whether a quote mark or something gets
>> interpreted or passed on.
>> Here are some examples:
>> $ cmd /c echo "/?"
>> Displays messages, or turns command-echoing on or off.
>> ECHO [ON | OFF]
>> ECHO [message]
>> Type ECHO without parameters to display the current echo setting.
>> # OK, so I'm getting the Windows echo, not the bash echo. Good.
>> # Moving on...
>> $ cmd /c echo abc
>> $ cmd /c echo "abc"
>> $ cmd /c echo "\"abc\""
>> # Wahhh?!
>> Anyone who knows the explanation would make me very grateful. I've tried
>> this with other Windows apps too, and the same weirdness seems to occur.
>All of the above is consistent with bash shell quoting. It's the shell that
>does the interpreting in the Unix/Linux world and that's what you're seeing here.
Huh? Last time I checked, bash translates "\"abc\"" to "abc".
>> On a related note, I've noticed what appears to be an automatic sort of
>half-bash invocation (but not quite?) or something when I run Cygwin
>commands from cmd.exe. For example,
>>> c:\cygwin\bin\echo hi
>>> c:\cygwin\bin\echo "hi"
>>> c:\cygwin\bin\echo "\"hi\""
>>> c:\cygwin\bin\echo *
>> myfile myotherfile yetanotherfile ...
>> And yet...
>>> c:\cygwin\bin\echo $PATH
>> What the heck is going on? Are there any rules here at all? Sorry if I'm
>> missing something dumb. And sorry for apologizing for it. And......
>In this case, the Cygwin DLL intercedes and handles quoting for the Cygwin
>you invoked (echo). But it only does quoting. You're mixing the notion of
>environment handling. They are two different things.
Does "handles quoting" mean that it implements the "Quoting" section, and only that section, of the bash manpage? I just need to know exactly what it does. It clearly does not *only* do quoting. That's why I demonstrated the asterisk example. It is doing at least wildcard expansion in addition to quoting. What else is it doing? I'm trying to figure this out so I know how to properly escape or quote a general command in order to execute it from a Windows application without any unexpected changes.
Thanks for the response,
Problem reports: http://cygwin.com/problems.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple