Fixed passing -0 to tail. Closes #10191

src/uu/tail/src/tail.rs

@@ -403,6 +403,10 @@ fn forwards_thru_file(
 /// `num_delimiters` instance of `delimiter`. The `file` is left seek'd to the
 /// position just after that delimiter.
 fn backwards_thru_file(file: &mut File, num_delimiters: u64, delimiter: u8) {
+    if num_delimiters == 0 {
+        file.seek(SeekFrom::End(0)).unwrap();
+        return;
+    }
     // This variable counts the number of delimiters found in the file
     // so far (reading from the end of the file toward the beginning).
     let mut counter = 0;

tests/by-util/test_tail.rs

@@ -1125,6 +1125,16 @@ fn test_obsolete_syntax_small_file() {
         .stdout_is("a\nb\nc\nd\ne\n");
 }
 
+/// Test for obsolete syntax `tail -0 FILE`: print nothing and exit cleanly.
+#[test]
+fn test_obsolete_syntax_zero_lines_file() {
+    new_ucmd!()
+        .args(&["-0", "foobar.txt"])
+        .succeeds()
+        .no_stderr()
+        .no_stdout();
+}
+
 /// Test for reading all lines, specified by `tail -n +0`.
 #[test]
 fn test_positive_zero_lines() {