Getting Windows "MACHINE SID" without fork() & exec()?

[René Berber]

On 4/23/2026 11:07 AM, Takeshi Nishimura via Cygwin wrote:

> Does Cygwin have a secret shell variable or /proc file which contains
> the current machine's MACHINE SID, without having to resort to calling
> an external program (no fork(), no exec(), please)?

Create your own environment variable.  Store it once per bash session 
with .bashrc for example, or permanently with all the other Windows 
variables.

Use PsGetSid to get the value into that variable (i.e. no super user 
access needed like with regtool.)
Ref: https://learn.microsoft.com/en-us/sysinternals/downloads/psgetsid

Caveat: The first time you run PsGetSid it shows a popup with the 
license agreement.

Example:
XPS-8930: ~
$ /home/reneb/bin/SysinternalsSuite/PsGetsid

PsGetSid v1.44 - Translates SIDs to names and vice versa
Copyright (C) 1999-2008 Mark Russinovich
Sysinternals - www.sysinternals.com

SID for \\XPS-8930:
S-1-5-21-3651791898-1415975337-2452924111

XPS-8930: ~
$ /home/reneb/bin/SysinternalsSuite/PsGetsid |& tail -n 3
S-1-5-21-3651791898-1415975337-2452924111


Hope this helps.
-- 
R.B.