sort: ignore failure to truncate the output file

src/uu/sort/src/sort.rs

@@ -173,7 +173,7 @@ impl Output {
         BufWriter::new(match self.file {
             Some((_name, file)) => {
                 // truncate the file
-                file.set_len(0).unwrap();
+                let _ = file.set_len(0);
                 Box::new(file)
             }
             None => Box::new(stdout()),

tests/by-util/test_sort.rs

@@ -1030,3 +1030,12 @@ fn test_output_is_input() {
     cmd.args(&["-m", "-o", "file", "file"]).succeeds();
     assert_eq!(at.read("file"), input);
 }
+
+#[test]
+#[cfg(unix)]
+fn test_output_device() {
+    new_ucmd!()
+        .args(&["-o", "/dev/null"])
+        .pipe_in("input")
+        .succeeds();
+}