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Date: Wed, 10 Mar 2010 08:15:20 -0700
From: Eric Blake <eblake AT redhat DOT com>
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To: cygwin AT cygwin DOT com
Subject: Re: allow executing a path in backslash notation
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On 03/10/2010 03:54 AM, Andy Koppe wrote:
>>> $ builtin exec "$WINDIR\system32\cmd.exe" /C echo ok
>>> -bash: exec: C:\WINDOWS\system32\cmd.exe: not found
>>>
>> Is it me, or is the quoting all wrong? Doesn't backslash in the double
>> quote (") acts as an escape character. i.e \s =3D s, \c =3D c etc.
>=20
> http://www.gnu.org/software/bash/manual/bashref.html#Double-Quotes:
> The backslash retains its special meaning only when followed by one of
> the following characters: =E2=80=98$=E2=80=99, =E2=80=98`=E2=80=99, =E2=
=80=98"=E2=80=99, =E2=80=98\=E2=80=99, or newline.

That's bash's rules.  According to POSIX, "\n" has undefined behavior.
And in some other implementations, such as Solaris sh, "\n" is
interpolated by the shell as a newline.  Bash instead does the
interpolation when you use $'\n'.

But the moral of the story is that within "", it is only portable to use
\ if it is followed by one of the four bytes specifically documented by
POSIX.

--=20
Eric Blake   eblake AT redhat DOT com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org


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