shell can launch another user processgit add .git add .!

programs/rocksh/main.c

@@ -1,3 +1,4 @@
+#include "syscall.h"
 #include <unistd.h>
 #include <stdio.h>
 #include <string.h>
@@ -7,6 +8,10 @@ const char* shell_prompt = "rocksh> ";
 char buf[256];
 size_t buf_offset = 0;
 
+char path[256];
+
+const char* bin_dir = "/bin/";
+
 void parse_cmd() {
     if (strcmp(buf, "exit") == 0) {
         printf("bye!\n");
@@ -15,7 +20,25 @@ void parse_cmd() {
 
     if (strcmp(buf, "motd")  == 0) {
         printf("rockos is the best!\n");
+        return;
     }
+
+    // need a strcat
+    char* dst = path;
+    strcpy(dst, bin_dir);
+    dst = path + strlen(bin_dir);
+    strcpy(dst, buf);
+
+    int pid = fork();
+    if (pid == 0) {
+        if (!exec(path)) {
+            return;
+        }
+    }
+
+    int status;
+    waitpid(pid, &status);
+    printf("process exited with status %d\n", status);
 }
 
 void reset() {