From 2a5610be455a966457111aa79a0e77c782dd53aa Mon Sep 17 00:00:00 2001
From: Wondr <wondr.design@gmail.com>
Date: Fri, 5 Jun 2026 11:45:49 +0100
Subject: [PATCH 1/2] grep: honor GNU buffer anchors

---
 src/matcher.rs     |  4 ++++
 tests/test_grep.rs | 27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/matcher.rs b/src/matcher.rs
index 783d239..6da6d9b 100644
--- a/src/matcher.rs
+++ b/src/matcher.rs
@@ -269,6 +269,10 @@ impl CompiledPattern {
             // GNU grep supports `{,n}` as an alias for `{0,n}`.
             syntax.enable_behavior(SyntaxBehavior::SYNTAX_BEHAVIOR_ALLOW_INTERVAL_LOW_ABBREV);
         }
+        if matches!(config.regex_mode, RegexMode::Basic | RegexMode::Extended) {
+            // GNU grep supports \` and \' as buffer anchors in BRE and ERE.
+            syntax.enable_operators(SyntaxOperator::SYNTAX_OPERATOR_ESC_GNU_BUF_ANCHOR);
+        }
         if config.regex_mode == RegexMode::Perl {
             // GNU grep supports `(?P<name>...)`.
             // Unfortunately, the onig crate defines the OP2 flag without the
diff --git a/tests/test_grep.rs b/tests/test_grep.rs
index fbea0a0..d190d98 100644
--- a/tests/test_grep.rs
+++ b/tests/test_grep.rs
@@ -85,6 +85,33 @@ fn bre_gnu_extensions() {
         .stdout_only("*foo\n**foo\n");
 }
 
+#[test]
+fn gnu_buffer_anchors() {
+    let (_s, mut c) = ucmd();
+    c.args(&[r"\`c"])
+        .pipe_in("cat\nscat\ndog\n")
+        .succeeds()
+        .stdout_only("cat\n");
+
+    let (_s, mut c) = ucmd();
+    c.args(&[r"t\'"])
+        .pipe_in("cat\ntar\ndog\n")
+        .succeeds()
+        .stdout_only("cat\n");
+
+    let (_s, mut c) = ucmd();
+    c.args(&["-E", r"\`c"])
+        .pipe_in("cat\nscat\ndog\n")
+        .succeeds()
+        .stdout_only("cat\n");
+
+    let (_s, mut c) = ucmd();
+    c.args(&["-E", r"t\'"])
+        .pipe_in("cat\ntar\ndog\n")
+        .succeeds()
+        .stdout_only("cat\n");
+}
+
 #[test]
 fn ere_metacharacters() {
     let cases: &[(&[&str], &str, &str)] = &[

From 0ec43c8f68dab26bc67e2085627ff0fee7f65603 Mon Sep 17 00:00:00 2001
From: Wondr <wondr.design@gmail.com>
Date: Fri, 5 Jun 2026 15:44:20 +0100
Subject: [PATCH 2/2] grep: compact buffer anchor tests

---
 tests/test_grep.rs | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/tests/test_grep.rs b/tests/test_grep.rs
index d190d98..6a42175 100644
--- a/tests/test_grep.rs
+++ b/tests/test_grep.rs
@@ -88,28 +88,16 @@ fn bre_gnu_extensions() {
 #[test]
 fn gnu_buffer_anchors() {
     let (_s, mut c) = ucmd();
-    c.args(&[r"\`c"])
-        .pipe_in("cat\nscat\ndog\n")
+    c.args(&[r"\`c\|r\'"])
+        .pipe_in("cat\nscat\ntar\ndog\n")
         .succeeds()
-        .stdout_only("cat\n");
+        .stdout_only("cat\ntar\n");
 
     let (_s, mut c) = ucmd();
-    c.args(&[r"t\'"])
-        .pipe_in("cat\ntar\ndog\n")
+    c.args(&["-E", r"\`c|r\'"])
+        .pipe_in("cat\nscat\ntar\ndog\n")
         .succeeds()
-        .stdout_only("cat\n");
-
-    let (_s, mut c) = ucmd();
-    c.args(&["-E", r"\`c"])
-        .pipe_in("cat\nscat\ndog\n")
-        .succeeds()
-        .stdout_only("cat\n");
-
-    let (_s, mut c) = ucmd();
-    c.args(&["-E", r"t\'"])
-        .pipe_in("cat\ntar\ndog\n")
-        .succeeds()
-        .stdout_only("cat\n");
+        .stdout_only("cat\ntar\n");
 }
 
 #[test]