From 134ed05e302efacf0089f807a287a068e39cae12 Mon Sep 17 00:00:00 2001
From: Johan Malm <jgm323@gmail.com>
Date: Fri, 15 Jul 2022 20:29:49 +0100
Subject: [PATCH] buf.c: fix bug in environment variable expansion

Allow underscore in environment variable names.

Closes issue #439

Helped-by: @Consolatis
...who both found the bug and told us how to fix it :)

Backport of fd7ec0ab95692dd7c9e8845c0786da149dc41dc1
---
 src/common/buf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/common/buf.c b/src/common/buf.c
index 5e908f9a..55d96078 100644
--- a/src/common/buf.c
+++ b/src/common/buf.c
@@ -29,7 +29,7 @@ buf_expand_shell_variables(struct buf *s)
 			environment_variable.len = 0;
 			buf_add(&environment_variable, s->buf + i + 1);
 			char *p = environment_variable.buf;
-			while (isalnum(*p) || *p == '{' || *p == '}') {
+			while (isalnum(*p) || *p == '_' || *p == '{' || *p == '}') {
 				++p;
 			}
 			*p = '\0';