diff --git a/line.c b/line.c
index 0a864c5..24d1786 100644
--- a/line.c
+++ b/line.c
@@ -4,14 +4,16 @@
  * @Last Modified by:   1ridic
  * @Last Modified time: 2022-09-18 14:14:05
  */
+#include "line.h"
 #include <stdio.h>
-#include <readline/readline.h>
-#include <readline/history.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include "line.h"
+#include <readline/history.h>
+#include <readline/readline.h>
 
+
+/*split one line to word, when appears "", save the content to one word*/
 char **splitLine(char *line) {
   int bufsize = LINE_BUF_SIZE, position = 0;
   char **tokens = malloc(bufsize * sizeof(char *));
@@ -29,6 +31,41 @@ char **splitLine(char *line) {
   token = strtok(line, " \t\r\n\a");
 
   while (token != NULL) {
+    /*detect if there exists "" pair*/
+    if (token[0] == '"') {
+      char *temp = malloc(bufsize * sizeof(char *));
+      for (int i = 0; i < strlen(token); i++) {
+        /*delete the first " */
+        temp[i] = token[i + 1];
+      }
+      /*read next token and detect " */
+      int pair_flag = 0;
+      while (1) {
+        token = strtok(NULL, " \t\r\n\a");
+        if (token[strlen(token) - 1] == '"') {
+          /*delete the last " */
+          token[strlen(token) - 1] = '\0';
+          strcat(temp, " ");
+          strcat(temp, token);
+          token=temp;
+          break;
+        } else {
+          strcat(temp, " ");
+          strcat(temp, token);
+          pair_flag = 1;
+        }
+        if(token==NULL&&pair_flag==0){
+          fprintf(stderr,"error: no pair \"\n");
+          return NULL;
+        }
+      }
+    }
+    else
+    {
+      char* temp=malloc(bufsize * sizeof(char *));
+      strcpy(temp,token);
+      token=temp;
+    }
     tokens[position] = token;
 #ifdef DEBUG
     fprintf(stdout, "debug: tokens[%d] = %s\n", position, tokens[position]);
diff --git a/loop.c b/loop.c
index 790306b..a428a70 100644
--- a/loop.c
+++ b/loop.c
@@ -4,23 +4,23 @@
  * @Last Modified by: 1ridic
  * @Last Modified time: 2022-09-20 22:26:59
  */
-#include <stdio.h>
-#include <readline/readline.h>
-#include <readline/history.h>
-#include <stdlib.h>
-#include <string.h>
 #include "loop.h"
 #include "exec.h"
 #include "line.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <readline/history.h>
+#include <readline/readline.h>
 
 int status;
 
 void SIGINT_Handler(int dummy) {
 #ifdef DEBUG
-  fprintf(stdout,"\ndebug: SIGINT\n");
+  fprintf(stdout, "\ndebug: SIGINT\n");
 #endif
   /* Move to a new line */
-  fprintf(stdout,"\n");
+  fprintf(stdout, "\n");
   /* Regenerate the prompt on a newline */
   rl_on_new_line();
   /* Clear the previous text */
@@ -33,11 +33,20 @@ int loop() {
 
   char *line;
   char **args;
-  line = readline(ANSI_COLOR_GREEN"> "ANSI_COLOR_RESET);
+  line = readline(ANSI_COLOR_GREEN "> " ANSI_COLOR_RESET);
   add_history(line);
   args = splitLine(line);
+  if (args == NULL) {
+    free(line);
+    free(args);
+    return 1;
+  }
   status = commandExec(args);
   free(line);
+  /*free all array in args*/
+  for (int i = 0; args[i] != NULL; i++) {
+    free(args[i]);
+  }
   free(args);
   return 0;
 }
\ No newline at end of file