Added catch command to hello.c

usr/hello/hello.c

@@ -15,17 +15,30 @@
 
 
 #include <stdio.h>
+#include <unistd.h>
+#include <string.h>
 
 #include <aos/aos.h>
 
+#define HELLO_CATCH_COMMAND "catch"
+
 int main(int argc, char *argv[])
 {
-    printf("Hello, world! from userspace\n");
+    printf("Hello, world!\n");
     
     printf("argv:\n");
     for(int i = 0; i < argc; ++i) {
         printf("  %d -> %s\n", i, argv[i]);
     }
 
+    // if we receive the catch command, RUN!
+    if (argc > 1 && !strncmp(argv[1], HELLO_CATCH_COMMAND, sizeof(HELLO_CATCH_COMMAND))) {
+        while(1) {
+            printf("Catch me if you can!\n");
+            // wait for 1 second
+            sleep(1);
+        }
+    }
+
     return EXIT_SUCCESS;
 }