From d5f4f5a944cb60f9068976d1d91e981d21c79cb2 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Fri, 7 Jul 2023 23:18:33 -0700
Subject: [PATCH] Add special '$GID' variable in Eshell

* lisp/eshell/esh-var.el (eshell-variable-aliases-list): Add '$GID'.
* test/lisp/eshell/esh-var-tests.el (esh-var-test/gid-var): New test.
* doc/misc/eshell.texi (Variables): Document '$GID'.
---
 doc/misc/eshell.texi              | 7 +++++++
 lisp/eshell/esh-var.el            | 1 +
 test/lisp/eshell/esh-var-tests.el | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/doc/misc/eshell.texi b/doc/misc/eshell.texi
index 5972d2834b0..a1f541da9da 100644
--- a/doc/misc/eshell.texi
+++ b/doc/misc/eshell.texi
@@ -993,6 +993,13 @@ Variables
 its value will be @acronym{UID} for the user associated with that
 remote connection.
 
+@vindex $GID
+@item $GID
+This returns the effective @acronym{GID} for the current user.  Like
+@code{$UID}, this variable is connection-aware, so when the current
+directory is remote, its value will be @acronym{GID} for the user
+associated with that remote connection.
+
 @vindex $_
 @item $_
 This refers to the last argument of the last command.  With a
diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index 7dcaff1e24f..c7c0a21d2a9 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -163,6 +163,7 @@ eshell-variable-aliases-list
     ("LINES" ,(lambda () (window-body-height nil 'remap)) t t)
     ("INSIDE_EMACS" eshell-inside-emacs t)
     ("UID" ,(lambda () (file-user-uid)) nil t)
+    ("GID" ,(lambda () (file-group-gid)) nil t)
 
     ;; for esh-ext.el
     ("PATH" (,(lambda () (string-join (eshell-get-path t) (path-separator)))
diff --git a/test/lisp/eshell/esh-var-tests.el b/test/lisp/eshell/esh-var-tests.el
index 771bd5a419c..3e58fe749dd 100644
--- a/test/lisp/eshell/esh-var-tests.el
+++ b/test/lisp/eshell/esh-var-tests.el
@@ -829,6 +829,10 @@ esh-var-test/uid-var
   "Test that $UID is equivalent to (user-uid) for local directories."
   (eshell-command-result-equal "echo $UID" (user-uid)))
 
+(ert-deftest esh-var-test/gid-var ()
+  "Test that $GID is equivalent to (group-gid) for local directories."
+  (eshell-command-result-equal "echo $GID" (group-gid)))
+
 (ert-deftest esh-var-test/last-status-var-lisp-command ()
   "Test using the \"last exit status\" ($?) variable with a Lisp command."
   (with-temp-eshell
-- 
2.25.1