diff --git a/fun_2.c b/fun_2.c
index 08787f7..1cbc401 100644
--- a/fun_2.c
+++ b/fun_2.c
@@ -13,8 +13,14 @@ void history(char *cmdline)
 
 void print_history(char *argv)
 {
-
-    int i = num - atoi(argv);
+    int i = 0;
+    if(argv == NULL)
+    {
+        for(; i<num; i++)
+            puts(storage[i]);
+        return;
+    }
+    i = num - atoi(argv);
     if(i < 0)
     {
         i = 0;
@@ -100,7 +106,6 @@ int Is_pipe(char **argv)
 void shell_direct(char **prog1, char **prog2)
 {    
     int fd;
-    if(prog1)
     if(fork() == 0)
     {   
         if( (fd=open(prog2[0],O_RDWR | O_CREAT | O_NOCTTY | O_NDELAY))<0 )
@@ -190,38 +195,4 @@ void mytop()
     
     return 1;
 }
-
-
-//tp 结构体
-//包含了进程指针p和ticks，对应某个进程和滴答
-struct tp {
-    struct proc *p;
-    u64_t ticks;
-};
-//计算cputicks 用到当前进程和其他进程的，还涉及CPUTIME
-u64_t cputicks(struct proc *p1, struct proc *p2, int timemode)
-{
-    int i;
-    u64_t t = 0;
-    //计算每个进程proc的滴答，通过proc和当前进程prev_proc做比较，如果endpoint相等，则在循环中分别计算
-    for(i = 0; i < CPUTIMENAMES; i++) {
-        if(!CPUTIME(timemode, i))
-            continue;
-        if(p1->p_endpoint == p2->p_endpoint) {
-            t = t + p2->p_cpucycles[i] - p1->p_cpucycles[i];
-        } else {
-            t = t + p2->p_cpucycles[i];
-        }
-    }
-//    for(i = 0; i < CPUTIMENAMES; i++) {
-//           if(!CPUTIME(timemode, i))
-//               continue;
-//           if(proc->p_endpoint == prev_proc->p_endpoint) {
-//               t = t + prev_proc->p_cpucycles[i] - proc->p_cpucycles[i];
-//           } else {
-//               t = t + prev_proc->p_cpucycles[i];
-//           }
-//       }
-    return t;
-}
 */
\ No newline at end of file
diff --git a/main b/main
index fd11ba0..1f5e5d4 100755
Binary files a/main and b/main differ