cat: handle CRLF delimiters correctly (#6763)

* fix issue #6248

* add test to cat for the case of issue #6248

src/uu/cat/src/cat.rs

@@ -540,9 +540,16 @@ fn write_new_line<W: Write>(
     state: &mut OutputState,
     is_interactive: bool,
 ) -> CatResult<()> {
-    if state.skipped_carriage_return && options.show_ends {
-        writer.write_all(b"^M")?;
+    if state.skipped_carriage_return {
+        if options.show_ends {
+            writer.write_all(b"^M")?;
+        } else {
+            writer.write_all(b"\r")?;
+        }
         state.skipped_carriage_return = false;
+
+        write_end_of_line(writer, options.end_of_line().as_bytes(), is_interactive)?;
+        return Ok(());
     }
     if !state.at_line_start || !options.squeeze_blank || !state.one_blank_kept {
         state.one_blank_kept = true;

tests/by-util/test_cat.rs

@@ -288,6 +288,15 @@ fn test_numbered_lines_no_trailing_newline() {
     // spell-checker:enable
 }
 
+#[test]
+fn test_numbered_lines_with_crlf() {
+    new_ucmd!()
+        .args(&["-n"])
+        .pipe_in("Hello\r\nWorld")
+        .succeeds()
+        .stdout_only("     1\tHello\r\n     2\tWorld");
+}
+
 #[test]
 fn test_stdin_show_nonprinting() {
     for same_param in ["-v", "-vv", "--show-nonprinting", "--show-non"] {