truncate: use map_err instead of unwrap_or_else

src/uu/truncate/src/truncate.rs

@@ -116,15 +116,13 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         .override_usage(&usage[..])
         .after_help(&long_usage[..])
         .try_get_matches_from(args)
-        .unwrap_or_else(|e| {
+        .map_err(|e| {
             e.print().expect("Error writing clap::Error");
             match e.kind {
-                clap::ErrorKind::DisplayHelp | clap::ErrorKind::DisplayVersion => {
-                    std::process::exit(0)
-                }
-                _ => std::process::exit(1),
+                clap::ErrorKind::DisplayHelp | clap::ErrorKind::DisplayVersion => 0,
+                _ => 1,
             }
-        });
+        })?;
 
     let files: Vec<String> = matches
         .values_of(options::ARG_FILES)