diff --git a/Makefile b/Makefile
index f068311..90062b1 100644
--- a/Makefile
+++ b/Makefile
@@ -17,3 +17,7 @@ run: run.c run.h
 
 util: util.c util.h
 	$(GCC) -c util.c
+
+clean:
+	rm chicken
+	rm *.o
diff --git a/README.md b/README.md
index b124d99..7f11ffd 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,6 @@
-# chickenshell
\ No newline at end of file
+# chickenshell
+
+
+## Reference
+
+[https://github.com/danistefanovic/build-your-own-x#build-your-own-shell](https://github.com/danistefanovic/build-your-own-x#build-your-own-shell)
diff --git a/chicken b/chicken
deleted file mode 100755
index 3bb43d9..0000000
Binary files a/chicken and /dev/null differ
diff --git a/error.h b/error.h
new file mode 100644
index 0000000..e1ef4ec
--- /dev/null
+++ b/error.h
@@ -0,0 +1,11 @@
+
+#ifndef ERRORH 
+#define ERRORH 
+
+enum ExitCodes {
+    ER_SUCCESS,
+    ER_FAILURE,
+    ER_FAIL_TO_FORK
+};
+
+#endif
diff --git a/main.c b/main.c
index 3da2818..b72276b 100644
--- a/main.c
+++ b/main.c
@@ -2,6 +2,8 @@
 #include <stdio.h>
 #include <stdbool.h>
 
+#include "error.h"
+
 #define INITIALLINEBUFFER 80
 
 char *readline(FILE* in) {
@@ -46,4 +48,5 @@ int main(int argc, char** argv) {
 
     exit(0);
 
+    return ER_SUCCESS;
 }
diff --git a/run.c b/run.c
index e69de29..9b47d2f 100644
--- a/run.c
+++ b/run.c
@@ -0,0 +1,37 @@
+#include "run.h"
+
+/* Fork and exec a command given in args taking input from in and sending 
+ * output to out. The arguments array must end in a NULL. 
+ *
+ * Returns true on success or 1 on failure.
+ */
+int execute(FILE *in, FILE *out, char *args[]) {
+    int in_FD = fileno(in);
+    int out_FD = fileno(out);
+
+    int err = fork();
+
+    if (err == -1) {
+        return ER_FAIL_TO_FORK;
+    }
+
+    if (err) {  // parent
+        return ER_SUCCESS;
+    } else {    // child
+        dup2(in_FD, 0);
+        dup2(out_FD, 1);
+
+        err = execvp(args[0], args);
+    }
+
+    return ER_SUCCESS;
+}
+
+int test_exec(void) {
+    char *arg[] = {"ls", "lah", 0};
+
+    execute(stdin, stdout, arg);
+
+    return 0;
+}
+
diff --git a/run.h b/run.h
index e69de29..4e3f57e 100644
--- a/run.h
+++ b/run.h
@@ -0,0 +1,18 @@
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "error.h"
+
+#ifndef RUNH
+#define RUNH
+
+/* Fork and exec a command given in args taking input from in and sending 
+ * output to out. The arguments array must end in a NULL. 
+ *
+ * Returns true on success or 1 on failure.
+ */
+int execute(FILE* in, FILE* out, char *args[]);
+
+#endif
diff --git a/util.h b/util.h
index e69de29..2e38fc4 100644
--- a/util.h
+++ b/util.h
@@ -0,0 +1,7 @@
+
+#ifndef UTILH
+#define UTILH
+
+
+
+#endif