From 8cd51227c61ddd40d94f38e4fb5022654382f0bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Teemu=20P=C3=A4tsi?= <frendsick@gmail.com>
Date: Sat, 26 Apr 2025 18:22:22 +0300
Subject: [PATCH 1/2] expr: Fix regex anchor matching behavior with
 `REGEX_OPTION_SINGLELINE`

The previously used `REGEX_OPTION_NONE` allowed anchors (^) and ($) to match across newlines.

New anchor behaviors:
- `^` matches the start of the entire string (`\A`)
- `$` matches the end of the entire string (`\Z`)
---
 src/uu/expr/src/syntax_tree.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/uu/expr/src/syntax_tree.rs b/src/uu/expr/src/syntax_tree.rs
index ac418cafeee..e6a5b347239 100644
--- a/src/uu/expr/src/syntax_tree.rs
+++ b/src/uu/expr/src/syntax_tree.rs
@@ -154,7 +154,7 @@ impl StringOp {
                 let re_string = format!("{prefix}{right}");
                 let re = Regex::with_options(
                     &re_string,
-                    RegexOptions::REGEX_OPTION_NONE,
+                    RegexOptions::REGEX_OPTION_SINGLELINE,
                     Syntax::grep(),
                 )
                 .map_err(|_| ExprError::InvalidRegexExpression)?;

From c6e2f9fd9a5283f27ae486d2cc52d01e6b8debfd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Teemu=20P=C3=A4tsi?= <frendsick@gmail.com>
Date: Sat, 26 Apr 2025 18:28:21 +0300
Subject: [PATCH 2/2] expr: Enable ignored test_anchor test

---
 tests/by-util/test_expr.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/by-util/test_expr.rs b/tests/by-util/test_expr.rs
index df2c27c1ce8..b49574f1533 100644
--- a/tests/by-util/test_expr.rs
+++ b/tests/by-util/test_expr.rs
@@ -618,7 +618,6 @@ mod gnu_expr {
             .stdout_only("1\n");
     }
 
-    #[ignore]
     #[test]
     fn test_anchor() {
         new_ucmd!()