Message-ID: <4D3CF157.9050705@cpan.org>
Date: Sun, 23 Jan 2011 22:26:15 -0500
From: Rafael Kitover <rkitover AT cpan DOT org>
Reply-To: rkitover AT cpan DOT org
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To: cygwin AT cygwin DOT com
Subject: Re: windows paths in shebang lines
References: <4D3CA1DA DOT 1000302 AT cpan DOT org> <4D3CB2ED DOT 5000801 AT bopp DOT net>
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On 1/23/2011 5:59 PM, Jeremy Bopp wrote:
> On 01/23/2011 03:47 PM, Rafael Kitover wrote:
>> When a script's shebang line has a windows path, rather than a cygwin
>> path, it does not work:
>>
>> rkitover AT eeebox ~
>> $ head -1 /cygdrive/c/Perl64/site/bin/ack
>> #!C:\Perl64\bin\perl
>>
>> rkitover AT eeebox ~
>> $ /cygdrive/c/Perl64/site/bin/ack --version
>> Can't open perl script "/cygdrive/c/Perl64/site/bin/ack": No such file
>> or directory
>>
>> On msys (msysGit) this works correctly:
>>
>> rkitover AT EEEBOX ~
>> $ /c/Perl64/site/bin/ack --version
>> ack 1.94
>> Running under Perl 5.12.2 at C:\Perl64\bin\perl.exe
>>
>> Copyright 2005-2010 Andy Lester.
>>
>> This program is free software.  You may modify or distribute it
>> under the terms of the Artistic License v2.0.
>>
>> Any chance this could be fixed? This would be a very nice feature for
>> users of Strawberry Perl and similar.
>
> The problem is not that you're using a Windows path instead of a Cygwin
> path in the shebang line; although, that is not officially supported
> under Cygwin.  Rather, the problem is that the version of Perl being run
> as a result of that shebang line does not understand Cygwin paths.
> That's why you see this error:
>
> Can't open perl script "/cygdrive/c/Perl64/site/bin/ack": No such file
> or directory
>
> That's the Perl interpreter telling you that it doesn't understand the
> path that was given to it for the ack script, so Perl is running at this
> point which means that the shebang line is understood correctly.  You
> should probably go read about how shebang lines work in general, but the
> short and sweet is that the shebang line is the first part of a command
> line to be run where the last part is the command line used to run the
> file that contains the shebang line itself.  IOW, the command line used
> in your first example is ultimately:
>
> C:\Perl64\bin\perl /cygdrive/c/Perl64/site/bin/ack --version

Ahh yes, I wasn't thinking about this clearly, thank you for the 
explanation :)

>
> You have 3 potential solutions to your problem:
>
> 1) Run Perl explicitly with the Windows path to the script as an argument:
>    /cygdrive/c/Perl64/bin/perl C:/Perl64/site/bin/ack
>
> 2) Change into the C: drive and use a relative path to the ack script
> when you run it:
>    cd /cygdrive/c
>    Perl64/site/bin/ack
>
> 3) Change your cygdrive mount location to / so that the path to the ack
> script will be /c/Perl64/site/bin/ack under Cygwin.
>
> Option 3 is the real hack.  I think it should work because it appears in
> your successful example that the Perl you want to use is able to
> translate paths such as /c/path/to/something to C:/path/to/something
> internally.  By adjusting the cygdrive mount location to /, you will
> cause Cygwin to send a compatible path to Perl when you run the script
> as /c/Perl64/site/bin/ack.
>
> -Jeremy

Unfortunately, that's not enough to get it to work:

$ /c/Perl64/site/bin/ack --version
Can't open perl script "/c/Perl64/site/bin/ack": No such file or directory

$ /c/Perl64/bin/perl /c/Perl64/site/bin/ack --version
Can't open perl script "/c/Perl64/site/bin/ack": No such file or directory

$ /c/Perl64/bin/perl /Perl64/site/bin/ack --version
ack 1.94
Running under Perl 5.12.2 at C:\Perl64\bin\perl.exe
...

msys seems to do something special for this to work correctly, it also 
seems to translate its paths to windows paths when running windows 
executables automatically, a very nice feature.

For this to work in cygwin I'd have to do something like mount c: as /, 
which I'm guessing would break absolutely everything :)

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