Re: Portable Cygwin: Hard-Coded Paths in a Restored Cygwin.bat File?

On 2025-08-04 17:30, Matthew Sheets via Cygwin-apps wrote:
> Are there two different versions of Cygwin.bat that Cygwin Setup could create depending on the context in which Cygwin Setup is executed?
> 
> If Cygwin setup is being used to create a new installation, the installed Cygwin.bat is fairly path independent:
> @echo off
> setlocal enableextensions
> set TERM=
> cd /d "%~dp0bin" && .\bash --login -i
> 
> 
> However, if Cygwin setup is being executed for an already-existing installation and restores a deleted Cygwin.bat, that restored Cygwin.bat contains hard-coded paths:
> @echo off
> C:
> chdir C:\Portable\Cygwin\arch-x86_64\bin
> bash --login -i

I still had one of the latter installed from 2013!

If you look at one of the base packages:

$ cygcheck -l base-files
/etc/defaults/Cygwin.bat
...
/etc/postinstall/base-files-profile.sh
/etc/preremove/base-files-manifest.lst
/etc/preremove/base-files.sh

it provides defaults and sets them up in the postinstall script driven by the 
manifest.

In our case, the ancient Cygwin.bat was always installed with a hard-coded path 
by Cygwin setup and never replaced, by design!

I just updated it from /etc/defaults/ so it looks like your first version.

You could also rm /Cygwin.bat and rerun /etc/postinstall/base-files-profile.sh, 
possibly with a .done suffix after Setup.

> For a portable setup, I am intending to remove and wrap Cygwin.bat and have _zero_ issue with Cygwin Setup restoring it (I was actually hoping Cygwin Setup _did_ restore Cygwin.bat so that any updates to Cygwin.bat could be incorporated), but the challenge here is that a completely different Cygwin.bat that contains hard-coded paths is created upon restoration.  Is this file content difference expected?  Could the `cd /d "%~dp0bin"` syntax be used in both cases (in place of the hardcoded paths)?

It has been and should be since at least 2016, when it was added to base-files; 
previously it was installed by Cygwin Setup and never updated if it existed:

	https://cygwin.com/cgit/cygwin-apps/setup/tree/desktop.cc?id=bf1d58#n163

[which is always a bad idea, as shown by the history of the single instruction 
program IEFBR14 which only returned to the IBM OS; until it needed to return 0, 
like `true`, after some system changes; then the assembler got stricter, so it 
needed overhead; and so on; see: https://en.wikipedia.org/wiki/IEFBR14
see also: https://www.miketaylor.org.uk/tech/oreilly/truenut.html ]

> As reference, the Cygwin Setup --version is 2.934 an the arguments passed to Cygwin Setup are as follows (PortableRoot and ARCH are set by the wrapper batch file that facilitates portability):
> ` --no-admin --no-shortcuts --no-write-registry --no-replaceonreboot --package-manager --root "%PortableRoot%\Cygwin\arch-%ARCH%"  --local-package-dir "%PortableRoot%\Cygwin\packages" --wait`
-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher  but when there is no more to cut
                                 -- Antoine de Saint-Exupéry