diff --git a/src/command.rs b/src/command.rs
index 64112cd..d46b1a3 100644
--- a/src/command.rs
+++ b/src/command.rs
@@ -92,7 +92,7 @@ impl Command for UnixProgram {
 
             let exit_code = match u8::try_from(exit_code) {
                 Ok(code) => ExitCode::new(code),
-                Err(_e) => ExitCode::new(255),
+                Err(_e) => ExitCode::new(u8::MAX),
             };
 
             exit_code