CygwinPaltform Identification

Brian Inglis
Wed Feb 9 01:46:07 GMT 2022

On 2022-02-08 15:01, wrote:
> Cygwin doesn't create an environment variable in bash to indicate that the
> platform is Cygwin under Windows.
> This causes compatibility problems when running various tools. Most of my
> issues have been with Python tools running Windows Python.
> I have been addressing this issue by grepping PATH for cygdrive which
> doesn't seem like a very good approach.
> Both msys2 and mingw solve this issue by setting the MSYSTEM environment
> variable which lets tools check that OS=Windows_NT and MSYSTEM=MSYS
> Please add some way of identifying that programs are running under Cygwin.

I have been switching env/OS/arch/triple dependent profile and rc files 
and sections for years with:

cygwin Windows_NT x86_64 x86_64-unknown-cygwin

cygwin Windows_NT i686 i686-pc-cygwin

Please note that *only* $OS is exported by default (in the above list), 
so you will have to explicitly export (in profiles) any other shell 
variables you wish to be available to shell subprocesses.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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