Test whether file is owned by a specific group from bash or powershell level?

[Sebastian Feld]

Does Cygwin or POSIX have a tool to test whether a file is owned by a
specific group?

Win32, like Linux and POSIX, has the concept that files have an owner,
and a group (ref:https://learn.microsoft.com/en-us/windows/win32/api/aclapi/nf-aclapi-getsecurityinfo).

How can I test whether a file is owned by a given group name, or not?
/usr/bin/test -g and -G do not help because they only look and gid,
egid. But I want to pass the group's name as an argument.

Sebi
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Sebastian Feld - IT security consultant