Cygwin Platform Identification

[Brian Inglis]

On 2022-02-09 02:12, Henry S. Thompson wrote:
> Brian Inglis writes:
> 
>> On 2022-02-08 15:01, julie77793@gmail.com wrote:
>>> Cygwin doesn't create an environment variable in bash to indicate that the
>>> platform is Cygwin under Windows.
>>> ...
>>
>> I have been switching env/OS/arch/triple dependent profile and rc files
>> and sections for years with:
>>
>> 64 $ echo $OSTYPE $OS $HOSTTYPE $MACHTYPE
>> cygwin Windows_NT x86_64 x86_64-unknown-cygwin
>> ...
> 
> When I don't know or can't remember what variable has the information
> I want, printenv is my first stop, e.g.
> 
>    64> printenv | grep -i cygwin
>    Cygwin=server
>    PATH=...
> 
> As Brian pointed out, that doesn't find what you need, because it only
> lists environment variables, but this does:
> 
>    64> declare -p | grep -i cygwin
>    declare -ar BASH_VERSINFO=([0]="4" [1]="4" [2]="12" [3]="3" [4]="release" [5]="x86_64-unknown-cygwin")
>    declare -x Cygwin="server"
>    declare -- MACHTYPE="x86_64-unknown-cygwin"
>    declare -- OSTYPE="cygwin"
>    declare -x PATH=...

AKA `set` in most shells:

$ set | egrep -i '=[^/\\]*(cygwin|windows)'
BASH_VERSINFO=([0]="4" [1]="4" [2]="12" [3]="3" [4]="release" 
[5]="x86_64-unknown-cygwin")
MACHTYPE=x86_64-unknown-cygwin
OS=Windows_NT
OSTYPE=cygwin
XDG_CURRENT_DESKTOP=X-Cygwin
$ env | egrep -i '=[^/\\]*(cygwin|windows)'
OS=Windows_NT
XDG_CURRENT_DESKTOP=X-Cygwin

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

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