diff --git a/result.txt b/result.txt
index 561402c..5c5a139 100755
--- a/result.txt
+++ b/result.txt
@@ -1,10 +1,5 @@
-total 56
-drwxr-xr-x   4 root root   120 Mar 16 23:39 .
-dr-xr-x---. 14 root root  4096 Mar 16 23:39 ..
-drwxr-xr-x   8 root root   201 Mar 16 22:49 .git
--rw-r--r--   1 root root    46 Mar 10 17:40 README.md
--rwx------   1 root root     0 Mar 16 23:39 result.txt
-drwxr-xr-x   2 root root    64 Mar 16 11:27 .vscode
--rwxr-xr-x   1 root root 27936 Mar 16 23:39 yeeshell
--rw-r--r--   1 root root 15053 Mar 16 23:38 yeeshell.c
--rw-r--r--   1 root root  4043 Mar 16 23:36 yeeshell.h
+README.md
+result.txt
+yeeshell
+yeeshell.c
+yeeshell.h
diff --git a/yeeshell b/yeeshell
index c8a9602..ca41902 100755
Binary files a/yeeshell and b/yeeshell differ
diff --git a/yeeshell.c b/yeeshell.c
index bed1ce3..1114bf2 100644
--- a/yeeshell.c
+++ b/yeeshell.c
@@ -15,18 +15,6 @@
 char *history[CMDLINE_HISTORY_MAX_QUANTITY];
 int cmdline_amount = 0;
 
-/* if true, print additional output */
-int verbose = 0;
-
-/* next job ID to allocate */
-int nextjid = 1;
-
-/* environment variable */
-extern char **environ;
-
-/* The job list */
-struct job_t jobs[JOBS_MAX_QUANTITY];
-
 int main()
 {
 	char *cmdline = NULL, *pwd = NULL;
@@ -38,15 +26,6 @@ int main()
 		history[i] = (char *)calloc(CMDLINE_MAX_SIZE, sizeof(char));
 	}
 
-	/* Install the signal handlers */
-	Signal(SIGINT, sigint_handler);	  /* ctrl-c */
-	Signal(SIGTSTP, sigtstp_handler); /* ctrl-z */
-	Signal(SIGCHLD, sigchld_handler); /* Terminated or stopped child */
-	Signal(SIGQUIT, sigquit_handler);
-
-	/* initiate job list */
-	initjobs(jobs);
-
 	/* execute the shell's read, parse and execution loop */
 	do
 	{
@@ -203,10 +182,6 @@ int execute(char *cmdline, char **args)
 	redirect_filename = (char *)calloc(REDIRECT_FILENAME_MAX_SIZE, sizeof(char));
 	memset(redirect_args, NULL, sizeof(redirect_args));
 
-	sigset_t mask_all, mask_prev;
-	sigprocmask(SIG_BLOCK, NULL, &mask_all);
-	sigaddset(&mask_all, SIGCHLD);
-
 	bg = parseline(cmdline, args);
 	redirect_flag = check_redirect(args, redirect_filename, redirect_args);
 	pipe_num = check_pipe(args, pipe_arg_1, pipe_arg_2);
@@ -215,13 +190,10 @@ int execute(char *cmdline, char **args)
 	{
 		return 1;
 	}
-	if (pipe_num == 0)
+	if (pipe_num == 0) /* no pipe */
 	{
 		if (!built_in(args)) /* built-in cmd? */
 		{
-			/* Prevent child processes from ending between parent processes, that is, between addJob and deleteJob. */
-			sigprocmask(SIG_BLOCK, &mask_all, &mask_prev); /* Shield SIGCHLD */
-
 			if ((pid = fork()) == 0) /* Child process */
 			{
 				if (redirect_flag == 1) /* redirect? */
@@ -237,14 +209,6 @@ int execute(char *cmdline, char **args)
 					dup(fd);
 				}
 
-				/* The child process inherits the parent's signal mask and will inherit it after exec, 
-           		 so it needs to restore the signal mask before executing. */
-				sigprocmask(SIG_SETMASK, &mask_prev, NULL); /* Child process, unblock SIGCHLD */
-
-				/* Set the pid of the current process to the group number of the process group it belongs to. */
-				/* avoid being grouped with tsh */
-				setpgid(0, 0);
-
 				if ((redirect_flag == 1) || (redirect_flag == 2))
 				{
 
@@ -264,27 +228,17 @@ int execute(char *cmdline, char **args)
 					}
 				}
 			}
-			else
+			else /* parent process */
 			{
-				if (bg) /* bg task */
+				if (bg)
 				{
-					addjob(jobs, pid, BG, cmdline);
+					signal(SIGCHLD, SIG_IGN);
 				}
-				else /* fg task */
-				{
-					addjob(jobs, pid, FG, cmdline);
-				}
-
-				sigprocmask(SIG_SETMASK, &mask_prev, NULL);
-
-				if (bg) /* Don't wait for background tasks to finish */
-				{
-					printf("[%d](%d)%s", pid2jid(pid), pid, cmdline);
-				}
-				else /* Wait for foreground tasks to finish */
+				else
 				{
-					waitfg(pid);
+					waitpid(pid, NULL, 0);
 				}
+				return 1;
 			}
 		}
 	}
@@ -292,7 +246,10 @@ int execute(char *cmdline, char **args)
 	{
 		int fds[2];
 		pid_t prog_1, prog_2;
-		sigprocmask(SIG_BLOCK, &mask_all, &mask_prev);
+
+		printf("%s %s %s %s %s %s\n", pipe_arg_1[0], pipe_arg_1[1], pipe_arg_1[3], pipe_arg_1[4], pipe_arg_1[5]);
+
+		printf("%s %s %s %s %s %s\n", pipe_arg_2[0], pipe_arg_2[1], pipe_arg_2[3], pipe_arg_2[4], pipe_arg_2[5]);
 
 		if ((prog_1 = fork()) == 0) /* Child process 1 */
 		{
@@ -300,16 +257,12 @@ int execute(char *cmdline, char **args)
 			dup2(fds[1], 2);
 			close(fds[0]);
 			close(fds[1]);
-
-			sigprocmask(SIG_SETMASK, &mask_prev, NULL);
 			setpgid(0, 0);
-
 			if (execvp(pipe_arg_1[0], pipe_arg_1) <= 0)
 			{
 				printf("%s: Command not found\n", pipe_arg_1[0]);
 				exit(0);
 			}
-			_exit(127);
 		}
 
 		if ((prog_2 = fork()) == 0) /* Child process 1 */
@@ -317,23 +270,21 @@ int execute(char *cmdline, char **args)
 			dup2(fds[0], 0);
 			close(fds[0]);
 			close(fds[1]);
-
-			sigprocmask(SIG_SETMASK, &mask_prev, NULL);
 			setpgid(0, 0);
-
 			if (execvp(pipe_arg_2[0], pipe_arg_2) <= 0)
 			{
 				printf("%s: Command not found\n", pipe_arg_2[0]);
 				exit(0);
 			}
-			_exit(127);
 		}
 
 		close(fds[0]);
 		close(fds[1]);
 
-		waitfg(prog_1);
-		waitfg(prog_2);
+		wait(0);
+		wait(0);
+
+		return 1;
 	}
 	return 1;
 }
@@ -354,11 +305,16 @@ int built_in(char **args)
 	}
 	else if (!strcmp(args[0], "mytop"))
 	{
-		return builtin_mytop(args);
-	}
-	else if (!strcmp(args[0], "jobs"))
-	{
-		return builtin_jobs(args);
+		int flag = builtin_mytop();
+		if (flag == -1)
+		{
+			printf("yeeshell: unable to get memory info.\n");
+		}
+		else if (flag == -2)
+		{
+			printf("yeeshell: unable to get CPU info.\n");
+		}
+		return flag;
 	}
 	else
 	{
@@ -401,343 +357,44 @@ int builtin_history(char **args)
 	return 1;
 }
 
-int builtin_jobs(char **args)
-{
-	/* To prevent interruptions, block all signals. */
-	sigset_t mask_all, mask_prev;
-	sigfillset(&mask_all);
-	sigprocmask(SIG_SETMASK, &mask_all, &mask_prev);
-
-	for (int i = 0; i < JOBS_MAX_QUANTITY; i++)
-	{
-		if (jobs[i].pid != 0)
-		{
-			printf("[%d] (%d) ", jobs[i].jid, jobs[i].pid);
-			switch (jobs[i].state)
-			{
-			case BG:
-				printf("Running ");
-				break;
-			case FG:
-				printf("Foreground ");
-				break;
-			case ST:
-				printf("Stopped ");
-				break;
-			default:
-				printf("listjobs: Internal error: job[%d].state=%d ",
-					   i, jobs[i].state);
-			}
-			printf("%s", jobs[i].cmdline);
-		}
-	}
-
-	sigprocmask(SIG_SETMASK, &mask_prev, NULL); /* unclock */
-	return 1;
-}
-
-int builtin_mytop(char **args)
+int builtin_mytop()
 {
-}
-
-int do_bgfg(char **args)
-{
-	/* initialize variables */
-	struct job_t *currentJob;
-	int jid;
-	pid_t pid;
-	sigset_t mask_all, mask_prev;
-	sigfillset(&mask_all);
-
-	sigprocmask(SIG_SETMASK, &mask_all, &mask_prev);
-
-	/* bg or fg has the argument? */
-	if (args[1] == NULL)
+	int memory_flag = 0, CPU_flag = 0;
+	memory_flag = mytop_memory();
+	CPU_flag = mytop_CPU();
+	if (!memory_flag)
 	{
-		printf("%s command requires PID or %%jobid argument\n", args[0]);
-		return 1;
+		return -1;
 	}
-	/* if process by jid, gets the corresponding Job structure*/
-	else if (args[1][0] == '%')
+	else if (!CPU_flag)
 	{
-		jid = atoi(args[1][1]);
-		currentJob = getjobjid(jobs, jid);
-		if (currentJob == NULL)
-		{
-			printf("%%%d: No such job\n", jid);
-			return 1;
-		}
-		pid = currentJob->pid;
+		return -2;
 	}
-	/* if process by pid, gets the corresponding Job structure */
 	else
 	{
-		pid = atoi(args[1]);
-		currentJob = getjobpid(jobs, pid);
-		if (pid <= 0)
-		{
-			printf("%s: argument must be a PID or %%jobid\n", args[0]);
-			return 1;
-		}
-		currentJob = getjobpid(jobs, pid);
-		if (currentJob == NULL)
-		{
-			printf("(%d): No such process\n", pid);
-			return 1;
-		}
-	}
-
-	/* bg or fg? */
-	if (!strcmp(args[0], "bg")) /* if bg */
-	{
-		currentJob->state = BG;
-		printf("[%d] (%d) %s", currentJob->jid, pid, currentJob->cmdline);
-		sigprocmask(SIG_SETMASK, &mask_prev, NULL);
-		kill(-pid, SIGCONT); /* send the SIGCONT to the pid */
-		return 1;
-	}
-	else if (!strcmp(args[0], "fg")) /* if fg */
-	{
-		currentJob->state = FG;
-		sigprocmask(SIG_SETMASK, &mask_prev, NULL);
-		kill(-pid, SIGCONT);	 /* send the SIGCONT to the pid */
-		waitfg(currentJob->pid); /* Child process switched to FG, so wait for it to finish */
 		return 1;
 	}
-	else if (!strcmp(args[0], "kill"))
-	{
-		sigprocmask(SIG_SETMASK, &mask_prev, NULL);
-		kill(-pid, SIGQUIT);
-		return 1;
-	}
-	return 1;
-}
-
-void waitfg(pid_t pid)
-{
-	sigset_t m;
-	sigemptyset(&m);
-	while (pid == fgpid(jobs))
-	{
-		/* Wake up when there is a signal to check whether the foreground process PID change, */
-		/* change means that the foreground process is over. */
-		sigsuspend(&m);
-	}
-	return;
-}
-
-void initjobs(struct job_t *jobs)
-{
-	int i;
-
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
-		clearjob(&jobs[i]);
-}
-
-int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline)
-{
-	int i;
-
-	if (pid < 1)
-		return 0;
-
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
-	{
-		if (jobs[i].pid == 0)
-		{
-			jobs[i].pid = pid;
-			jobs[i].state = state;
-			jobs[i].jid = nextjid++;
-			if (nextjid > JOBS_MAX_QUANTITY)
-				nextjid = 1;
-			strcpy(jobs[i].cmdline, cmdline);
-
-			if (verbose)
-			{
-				printf("Added job [%d] %d %s\n", jobs[i].jid, jobs[i].pid, jobs[i].cmdline);
-			}
-			return 1;
-		}
-	}
-	printf("Tried to create too many jobs\n");
-	return 0;
-}
-
-void listjobs(struct job_t *jobs)
-{
-	for (int i = 0; i < JOBS_MAX_QUANTITY; i++)
-	{
-		if (jobs[i].pid != 0)
-		{
-			printf("[%d] (%d) ", jobs[i].jid, jobs[i].pid);
-			switch (jobs[i].state)
-			{
-			case BG:
-				printf("Running ");
-				break;
-			case FG:
-				printf("Foreground ");
-				break;
-			case ST:
-				printf("Stopped ");
-				break;
-			default:
-				printf("listjobs: Internal error: job[%d].state=%d ", i, jobs[i].state);
-			}
-			printf("%s", jobs[i].cmdline);
-		}
-	}
 }
 
-int deletejob(struct job_t *jobs, pid_t pid)
+int mytop_memory()
 {
-	int i;
+	FILE *fp = NULL;
+	int pagesize;
+	long total = 0, free = 0, cached = 0;
 
-	if (pid < 1)
-		return 0;
-
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
+	if ((fp = fopen("/proc/meminfo", "r")) == NULL)
 	{
-		if (jobs[i].pid == pid)
-		{
-			clearjob(&jobs[i]);
-			nextjid = maxjid(jobs) + 1;
-			return 1;
-		}
-	}
-	return 0;
-}
-
-void clearjob(struct job_t *job)
-{
-	job->pid = 0;
-	job->jid = 0;
-	job->state = UNDF;
-	job->cmdline[0] = '\0';
-}
-
-int pid2jid(pid_t pid)
-{
-	int i;
-
-	if (pid < 1)
 		return 0;
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
-		if (jobs[i].pid == pid)
-		{
-			return jobs[i].jid;
-		}
-	return 0;
-}
-
-pid_t fgpid(struct job_t *jobs)
-{
-	for (int i = 0; i < JOBS_MAX_QUANTITY; i++)
-		if (jobs[i].state == FG)
-			return jobs[i].pid;
-	return 0;
-}
-
-struct job_t *getjobpid(struct job_t *jobs, pid_t pid)
-{
-	int i;
-
-	if (pid < 1)
-		return NULL;
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
-		if (jobs[i].pid == pid)
-			return &jobs[i];
-	return NULL;
-}
-
-struct job_t *getjobjid(struct job_t *jobs, int jid)
-{
-	int i;
-
-	if (jid < 1)
-		return NULL;
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
-		if (jobs[i].jid == jid)
-			return &jobs[i];
-	return NULL;
-}
-
-int maxjid(struct job_t *jobs)
-{
-	int i, max = 0;
-
-	for (i = 0; i < JOBS_MAX_QUANTITY; i++)
-	{
-		if (jobs[i].jid > max)
-		{
-			max = jobs[i].jid;
-		}
 	}
-	return max;
-}
-
-handler_t *Signal(int signum, handler_t *handler)
-{
-	struct sigaction action, old_action;
-
-	action.sa_handler = handler;
-	sigemptyset(&action.sa_mask); /* block sigs of type being handled */
-	action.sa_flags = SA_RESTART; /* restart syscalls if possible */
-
-	if (sigaction(signum, &action, &old_action) < 0)
-		fprintf(stdout, "%s: %s\n", 'Signal Error', strerror(errno));
-	return (old_action.sa_handler);
-}
 
-void sigchld_handler(int signal)
-{
-	pid_t pid;
-	int status;
-	while ((pid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0)
-	{
-		if (WIFEXITED(status)) /* Normal termination */
-		{
-			deletejob(jobs, pid);
-		}
-		if (WIFSTOPPED(status)) /* Task suspension */
-		{
-			struct job_t *job = getjobpid(jobs, pid);
-			int jid = pid2jid(pid);
-			printf("Job [%d] (%d) stopped by signal %d\n", jid, pid, WSTOPSIG(status));
-			job->state = ST;
-		}
-		if (WIFSIGNALED(status)) /* Task terminated */
-		{
-			int jid = pid2jid(pid);
-			printf("Job [%d] (%d) terminated by signal %d\n", jid, pid, WTERMSIG(status));
-			deletejob(jobs, pid);
-		}
-	}
-	return;
-}
+	fscanf(fp, "%u %lu %lu %lu", &pagesize, &total, &free, &cached);
+	fclose(fp);
 
-void sigint_handler(int signal)
-{
-	pid_t pid = fgpid(jobs);
-	if (pid != 0)
-	{
-		kill(-pid, signal);
-	}
-	return;
-}
+	printf("memmory(KBytes):\t%ld total\t%ld free\t%ld cached\n", (pagesize * total) / 1024, (pagesize * free) / 1024, (pagesize * cached) / 1024);
 
-void sigtstp_handler(int signal)
-{
-	pid_t pid = fgpid(jobs);
-	if (pid > 0)
-	{
-		kill(-pid, signal);
-	}
-	return;
+	return 1;
 }
 
-void sigquit_handler(int signal)
+int mytop_CPU()
 {
-	printf("Terminating after receipt of SIGQUIT signal\n");
-	exit(1);
 }
\ No newline at end of file
diff --git a/yeeshell.h b/yeeshell.h
index eb16d4a..a26c1f8 100644
--- a/yeeshell.h
+++ b/yeeshell.h
@@ -2,33 +2,19 @@
 
 #define CMDLINE_MAX_SIZE 1024 /* max length of a single command line */
 #define ARGS_MAX_QUANTITY 128 /* max args on a command line */
-#define BUFFER_MAX_SIZE 64	  /* max size of a buffer which contains parsed arguments */
+#define BUFFER_MAX_SIZE 64    /* max size of a buffer which contains parsed arguments */
 #define CMDLINE_DIV ' \t\r\n\a'
 #define CMDLINE_HISTORY_MAX_QUANTITY 256
 #define JOBS_MAX_QUANTITY 16
 #define PATH_MAX_SIZE 256
 #define LS_BUF_SIZE 1024
 #define REDIRECT_FILENAME_MAX_SIZE 64 /* redirection filename */
-#define REDIRECT_ARG_MAX_SIZE 16	  /* redirection argument */
-
-#define UNDF 0 /* undefined */
-#define FG 1   /* running in foreground */
-#define BG 2   /* running in background */
-#define ST 3   /* stopped */
+#define REDIRECT_ARG_MAX_SIZE 16      /* redirection argument */
 
 #define REDIRECT_NO 0  /* no redirection */
 #define REDIRECT_OUT 1 /* redirect output */
 #define REDIRECT_IN 2  /* redirect input */
 
-/* job_t - The job struct */
-struct job_t
-{
-	pid_t pid;						/* job PID */
-	int jid;						/* job ID [1, 2, ...] */
-	int state;						/* UNDEF, BG, FG, or ST */
-	char cmdline[CMDLINE_MAX_SIZE]; /* command line */
-};
-
 /* readline - Get the command line */
 char *readline();
 
@@ -48,75 +34,4 @@ int execute(char *cmdline, char **args);
 int built_in(char **args);
 int builtin_cd(char **args);
 int builtin_history(char **args);
-int builtin_jobs(char **args);
-int builtin_mytop(char **args);
-
-/* do_bgfg - Execute background/foregroung tasks */
-int do_bgfg(char **args);
-
-/* waitfg - Wait foreground jobs to finish */
-void waitfg(pid_t pid);
-
-/* initjobs - Initialize the job list */
-void initjobs(struct job_t *jobs);
-
-/* addjob - Add jobs to joblist */
-int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline);
-
-/* listjobs - Print the job list */
-void listjobs(struct job_t *jobs);
-
-/* deletejob - Delete a job whose PID=pid from the job list */
-int deletejob(struct job_t *jobs, pid_t pid);
-
-/* clearjob - Clear the entries in a job struct */
-void clearjob(struct job_t *job);
-
-/* pide2jid - Map process ID to job ID*/
-int pid2jid(pid_t pid);
-
-/* fgpid - Return PID of current foreground job, 0 if no such job */
-pid_t fgpid(struct job_t *jobs);
-
-/* getjobpid - Find a job (by PID) on the job list */
-struct job_t *getjobpid(struct job_t *jobs, pid_t pid);
-
-/* getjobjid  - Find a job (by JID) on the job list */
-struct job_t *getjobjid(struct job_t *jobs, int jid);
-
-/* maxjid - Returns largest allocated job ID */
-int maxjid(struct job_t *jobs);
-
-/* Signal - wrapper for the sigaction function */
-typedef void handler_t(int);
-handler_t *Signal(int signum, handler_t *handler);
-
-/* 
- * sigchld_handler - The kernel sends a SIGCHLD to the shell whenever
- *     a child job terminates (becomes a zombie), or stops because it
- *     received a SIGSTOP or SIGTSTP signal. The handler reaps all
- *     available zombie children, but doesn't wait for any other
- *     currently running children to terminate.  
- */
-void sigchld_handler(int signal);
-
-/* 
- * sigint_handler - The kernel sends a SIGINT to the shell whenver the
- *    user types ctrl-c at the keyboard.  Catch it and send it along
- *    to the foreground job.  
- */
-void sigint_handler(int signal);
-
-/*
- * sigtstp_handler - The kernel sends a SIGTSTP to the shell whenever
- *     the user types ctrl-z at the keyboard. Catch it and suspend the
- *     foreground job by sending it a SIGTSTP.  
- */
-
-void sigtstp_handler(int signal);
-
-/*
- * sigquit_handler - The driver program can gracefully terminate the
- *    child shell by sending it a SIGQUIT signal.
- */
-void sigquit_handler(int signal);
\ No newline at end of file
+int builtin_mytop();
\ No newline at end of file