touch: add -f flag (#8274)

* touch: fix f flag

* Update src/uu/touch/src/touch.rs

Co-authored-by: Sylvestre Ledru <[email protected]>

* touch: add test for f flag

* Update src/uu/touch/src/touch.rs

Co-authored-by: Daniel Hofstetter <[email protected]>

* Update tests/by-util/test_touch.rs

Co-authored-by: Daniel Hofstetter <[email protected]>

* remove unnecessary comment

---------

Co-authored-by: Sylvestre Ledru <[email protected]>
Co-authored-by: Daniel Hofstetter <[email protected]>

Author: 3 people

src/uu/touch/src/touch.rs

@@ -99,6 +99,7 @@ pub mod options {
     pub static NO_CREATE: &str = "no-create";
     pub static NO_DEREF: &str = "no-dereference";
     pub static TIME: &str = "time";
+    pub static FORCE: &str = "force";
 }
 
 static ARG_FILES: &str = "files";
@@ -291,6 +292,13 @@ pub fn uu_app() -> Command {
                 .value_name("STRING")
                 .conflicts_with(options::sources::TIMESTAMP),
         )
+        .arg(
+            Arg::new(options::FORCE)
+                .short('f')
+                .help("(ignored)")
+                .hide(true)
+                .action(ArgAction::SetTrue),
+        )
         .arg(
             Arg::new(options::MODIFICATION)
                 .short('m')

tests/by-util/test_touch.rs

@@ -1006,3 +1006,14 @@ fn test_obsolete_posix_format_with_year() {
     assert!(at.file_exists("11111111"));
     assert!(!at.file_exists("0101000090"));
 }
+
+#[test]
+fn test_touch_f_option() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let file = "test_f_option.txt";
+
+    ucmd.args(&["-f", file]).succeeds().no_output();
+
+    assert!(at.file_exists(file));
+    at.remove(file);
+}