diff --git a/always-rebuild.do b/always-rebuild.do
new file mode 100644
index 0000000..06fcfe0
--- /dev/null
+++ b/always-rebuild.do
@@ -0,0 +1,2 @@
+redo-always
+redo-ifchange release
diff --git a/release.do b/release.do
new file mode 100644
index 0000000..8ce97db
--- /dev/null
+++ b/release.do
@@ -0,0 +1,4 @@
+redo-ifchange Cargo.toml
+find src/ -type f | xargs redo-ifchange
+
+cargo build --release
diff --git a/src/main.rs b/src/main.rs
index cdb9fd2..072b70e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -446,10 +446,21 @@ globalThis.runOnInput = function(data) {
     // now. Another way to do this would be with an Arc. This will panic if the
     // mailbox is currently borrowed
     match mailbox.replace(None) {
-        Some(Ok(output)) => {
-            io::stdout()
-                .write_all(&output)
-                .map_err(|io_err| CompilerError::WriteOutputFailed(io_err, "stdout".into()))?;
+        Some(Ok(buffer)) => {
+            match output {
+                None => {
+                    io::stdout()
+                        .write_all(&buffer)
+                        .map_err(|io_err| CompilerError::WriteOutputFailed(io_err, "stdout".into()))?;
+                },
+                Some(filename) => {
+                    let mut f = fs::File::create(&filename)
+                        .map_err(|io_err| CompilerError::WriteOutputFailed(io_err, filename))?;
+                    
+                    f.write_all(&buffer)
+                        .map_err(|io_err| CompilerError::WriteOutputFailed(io_err, "stdout".into()))?;
+                }
+            }
         }
         Some(Err(problem)) => {
             println!("had a problem {}", problem);
diff --git a/starmelon-binary.do b/starmelon-binary.do
new file mode 100644
index 0000000..43a6053
--- /dev/null
+++ b/starmelon-binary.do
@@ -0,0 +1,7 @@
+if test -f ../../target/debug/gen-css-selectors; then
+    redo-ifchange always-rebuild
+    ls -al ../../../target/release/starmelon | redo-stamp
+else;
+    cargo build --release
+    ls -al ../../../target/release/starmelon | redo-stamp
+fi