From 1ad10dd371cfe341993c23d302c7a002a85953ae Mon Sep 17 00:00:00 2001
From: Terts Diepraam <terts.diepraam@gmail.com>
Date: Tue, 29 Aug 2023 21:54:19 +0200
Subject: [PATCH] echo: add support for \NNN octal escape sequence

---
 src/uu/echo/src/echo.rs    | 10 ++++++++++
 tests/by-util/test_echo.rs | 27 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/src/uu/echo/src/echo.rs b/src/uu/echo/src/echo.rs
index 4aba703a1..565166842 100644
--- a/src/uu/echo/src/echo.rs
+++ b/src/uu/echo/src/echo.rs
@@ -54,6 +54,16 @@ fn print_escaped(input: &str, mut output: impl Write) -> io::Result<bool> {
             continue;
         }
 
+        // This is for the \NNN syntax for octal sequences.
+        // Note that '0' is intentionally omitted because that
+        // would be the \0NNN syntax.
+        if let Some('1'..='8') = iter.peek() {
+            if let Some(parsed) = parse_code(&mut iter, 8, 3) {
+                write!(output, "{parsed}")?;
+                continue;
+            }
+        }
+
         if let Some(next) = iter.next() {
             let unescaped = match next {
                 '\\' => '\\',
diff --git a/tests/by-util/test_echo.rs b/tests/by-util/test_echo.rs
index 82137c715..7de963973 100644
--- a/tests/by-util/test_echo.rs
+++ b/tests/by-util/test_echo.rs
@@ -253,3 +253,30 @@ fn wrapping_octal() {
         .succeeds()
         .stdout_is("A\n");
 }
+
+#[test]
+fn old_octal_syntax() {
+    new_ucmd!()
+        .arg("-e")
+        .arg("\\1foo")
+        .succeeds()
+        .stdout_is("\x01foo\n");
+
+    new_ucmd!()
+        .arg("-e")
+        .arg("\\43foo")
+        .succeeds()
+        .stdout_is("#foo\n");
+
+    new_ucmd!()
+        .arg("-e")
+        .arg("\\101foo")
+        .succeeds()
+        .stdout_is("Afoo\n");
+
+    new_ucmd!()
+        .arg("-e")
+        .arg("\\1011")
+        .succeeds()
+        .stdout_is("A1\n");
+}