xv6 shell

来源：互联网发布：淘宝上刷q币是真的吗编辑：程序博客网时间：2024/06/05 00:59

1、在home下新建shell.c文件，拷贝原有代码，并修改runcmd部分：

void runcmd(struct cmd *cmd){    int p[2], r;    struct execcmd *ecmd;    struct pipecmd *pcmd;    struct redircmd *rcmd;    if(cmd == 0)        exit(0);    switch(cmd->type)    {    default:        fprintf(stderr, "unknown runcmd\n");        exit(-1);    case ' ':        ecmd = (struct execcmd*)cmd;        if(ecmd->argv[0] == 0)            exit(0);      // fprintf(stderr, "exec not implemented\n");             // system(ecmd->argv[0]);  // Your code here ...      // execl("/bin/sh", "sh", "-c", ecmd->argv[0], (char *)0);     execvp(ecmd->argv[0],ecmd->argv);     break;    case '>':    case '<':        rcmd = (struct redircmd*)cmd;        FILE *stream;        if(rcmd->fd == 1)        stream  =  freopen(rcmd->file,"w",stdout);             else           freopen(rcmd->file,"r",stdin);                if(stream == NULL)             fprintf(stderr,"errorredirecting\n");         else{               runcmd(rcmd->cmd);           fclose(stream);         }        break;    case '|':        pcmd = (struct pipecmd*)cmd;        int p[2];        if(pipe(p) < 0)           fprintf(stderr,"pipe not implemented\n");           if(pipe(p) == 0){           if(fork1() == 0){              close(1);              dup2(p[1],1);              close(p[0]);              runcmd(pcmd->left);         }        else{          close(0);          dup2(p[0],0);          close(p[1]);           runcmd(pcmd->right);        }   }     // Your code here ...        break;    }    exit(0);}

2、在home下新建t.sh文件，输入如下代码：

ls > ycat < y | sort | uniq | wc > y1cat y1ls | sort | uniq | wcrm y

3、运行结果如下图所示：

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