{"id":116359,"date":"2026-10-21T08:17:27","date_gmt":"2026-10-21T00:17:27","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/116359.html"},"modified":"2026-10-21T08:17:27","modified_gmt":"2026-10-21T00:17:27","slug":"%e3%80%90linux%e3%80%91-%e8%87%aa%e4%b8%bbshell%e7%bc%96%e5%86%99%e5%b7%a9%e5%9b%ba%e5%a4%8d%e4%b9%a0%e7%af%87","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/116359.html","title":{"rendered":"\u3010Linux\u3011 \u81ea\u4e3bshell\u7f16\u5199\u5de9\u56fa\u590d\u4e60\u7bc7"},"content":{"rendered":"

\/* MD \/ \u5bcc\u6587\u672c\u4e2d\u7684 .toc\uff08\u542b\u535a\u5ba2\u56ed\u642c\u5bb6\u7b49\u5d4c\u5957\u7ed3\u6784\uff09\uff1b.toc-box \u5728\u4fa7\u680f\uff0c\u4e0d\u53d7\u5f71\u54cd *\/
\n #content_views .toc,
\n \/* \u7f16\u8f91\u5668\u5e38\u5728\u76ee\u5f55\u524d\u540e\u63d2\u5165\u7a7a p\uff08:empty \u4ecd\u5360 20px\uff09\uff0c\u4e00\u5e76\u53bb\u6389\u907f\u514d\u9876\u7a7a\u9699 *\/
\n #content_views.markdown_views > p:empty:has(+ .toc),
\n #content_views.markdown_views > .toc + p:empty,
\n \/* \u5bcc\u6587\u672c\u65e7\u7248\u76ee\u5f55\u6807\u8bb0 *\/
\n #content_views.htmledit_views #main-toc,
\n #content_views.htmledit_views #hr-toc,
\n #content_views.htmledit_views p[id*=\\”-toc\\”] {
\n display: none !important;
\n }
\n \/* \u76ee\u5f55\u53bb\u6389\u540e\uff0c\u7d27\u8ddf\u7684\u9996\u4e2a\u6807\u9898\u4e0d\u518d\u591a\u51fa\u4e00\u5757\u4e0a\u8fb9\u8ddd *\/
\n #content_views.markdown_views > .toc + h1,
\n #content_views.markdown_views > .toc + h2,
\n #content_views.markdown_views > .toc + h3,
\n #content_views.markdown_views > .toc + h4,
\n #content_views.markdown_views > .toc + p:empty + h1,
\n #content_views.markdown_views > .toc + p:empty + h2,
\n #content_views.markdown_views > .toc + p:empty + h3,
\n #content_views.markdown_views > .toc + p:empty + h4 {
\n margin-top: 0 !important;
\n }<\/p>\n

\"\"<\/p>\n

\n

\"\"<\/span><\/p>\n

\u4e00\u3001\u5168\u5c40\u914d\u7f6e\u4e0e\u72b6\u6001（\u4ee3\u7801\u6700\u5f00\u5934）<\/span><\/h3>\n\n\u53d8\u91cf<\/span>\u7c7b\u578b<\/span>\u4f5c\u7528<\/span><\/tr>\n\n\n\n\n\n\n\n\n\n
basesize = 1024<\/span><\/td>\nconst int<\/span><\/td>\n\u547d\u4ee4\u884c\u7f13\u51b2\u533a\u548c pwd \u7f13\u51b2\u533a\u5927\u5c0f<\/span><\/td>\n<\/tr>\n
argvnum = 64<\/span><\/td>\nconst int<\/span><\/td>\ngargv \u6700\u591a\u5b58 64 \u4e2a\u53c2\u6570<\/span><\/td>\n<\/tr>\n
envnum = 64<\/span><\/td>\nconst int<\/span><\/td>\n\u81ea\u7ef4\u62a4\u73af\u5883\u8868 genv \u6700\u591a 64 \u9879<\/span><\/td>\n<\/tr>\n
gargv[64]<\/span><\/td>\nstatic char*[]<\/span><\/td>\n\u89e3\u6790\u540e\u7684\u53c2\u6570\u8868，\u672b\u5c3e\u5fc5\u987b NULL（exec \u65cf\u8981\u6c42）<\/span><\/td>\n<\/tr>\n
gargc<\/span><\/td>\nstatic int<\/span><\/td>\n\u53c2\u6570\u4e2a\u6570<\/span><\/td>\n<\/tr>\n
lastcode<\/span><\/td>\nstatic int<\/span><\/td>\n\u4e0a\u4e00\u6761\u547d\u4ee4\u9000\u51fa\u7801，echo $? \u5c31\u8bfb\u5b83<\/span><\/td>\n<\/tr>\n
genv[64]<\/span><\/td>\nstatic char*[]<\/span><\/td>\nshell \u81ea\u5df1\u7ef4\u62a4\u7684\u73af\u5883\u53d8\u91cf\u8868（\u540e\u9762\u91cd\u70b9\u8bb2）<\/span><\/td>\n<\/tr>\n
pwd[1024] \/ pwdenv[1024]<\/span><\/td>\nstatic char[]<\/span><\/td>\n\u5f53\u524d\u76ee\u5f55 \/ \u62fc\u597d\u7684 "PWD=xxx" \u5b57\u7b26\u4e32<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u51e0\u4e2a\u8bbe\u8ba1\u8981\u70b9：<\/span><\/p>\n

    \n
  • \u8fd9\u4e9b\u90fd\u662f\u5168\u5c40 static，\u751f\u547d\u5468\u671f\u7b49\u4e8e\u6574\u4e2a\u7a0b\u5e8f，\u540e\u7eed\u51fd\u6570\u968f\u4fbf\u7528\u3002<\/span><\/li>\n
  • gargv \u662f char* \u6570\u7ec4，\u6307\u5411\u547d\u4ee4\u884c\u7f13\u51b2\u533a\u5185\u90e8\u7684\u5404\u4e2a\u5355\u8bcd（strtok \u539f\u5730\u5207\u51fa\u6765\u7684），\u4e0d\u662f\u62f7\u8d1d\u3002<\/span><\/li>\n
  • lastcode \u662f\u6574\u4e2a shell \u7684\u72b6\u6001\u6838\u5fc3\u2014\u2014echo $? \u7684 $? \u4e0d\u662f\u7cfb\u7edf\u53d8\u91cf，\u5c31\u662f\u6253\u5370\u8fd9\u4e2a\u53d8\u91cf\u3002<\/span><\/li>\n<\/ul>\n
    \n

    \u4e8c\u3001\u63d0\u793a\u7b26\u51fd\u6570\u7ec4（6 \u4e2a\u51fd\u6570，\u4f5c\u7528\u4e00\u6761\u94fe）<\/span><\/h3>\n

    GetUserName \u2192 GetHostName \u2192 GetPwd \u2192 LastDir \u2192 MakeCommandLine \u2192 PrintCommandLine<\/p>\n

    GetUserName \/ GetHostName：<\/span><\/p>\n

    \u00a0\u00a0\u00a0getenv("USER")\u3001getenv("HOSTNAME")，\u4ece\u8fdb\u7a0b\u73af\u5883\u8868\u8bfb\u7528\u6237\u540d\u548c\u4e3b\u673a\u540d\u3002<\/span><\/p>\n

    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u627e\u4e0d\u5230\u8fd4\u56de "None"\u3002<\/span><\/p>\n

    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u6ce8\u610f getenv \u8fd4\u56de\u7684\u6307\u9488\u662f\u53ea\u8bfb\u7684（\u6307\u5411 environ \u8868\u5185\u90e8），\u4e0d\u8981\u5c1d\u8bd5\u4fee\u6539\u3002<\/span><\/p>\n<\/p>\n

    GetPwd（\u542b\u4e00\u4e2a\u5173\u952e\u52a8\u4f5c）：<\/span><\/p>\n

    if (getcwd(pwd, sizeof(pwd)) == NULL) return "None";
    \nsnprintf(pwdenv, sizeof(pwdenv), "PWD=%s", pwd);
    \nputenv(pwdenv);<\/p>\n

      \n
    • getcwd \u662f\u7cfb\u7edf\u8c03\u7528：\u95ee\u5185\u6838"\u6211\u7684\u5f53\u524d\u5de5\u4f5c\u76ee\u5f55\u5728\u54ea"，\u7ed3\u679c\u5199\u5165 pwd\u3002<\/span><\/li>\n
    • snprintf \u62fc\u51fa "PWD=\/home\/xx" \u5b58\u8fdb\u5168\u5c40 pwdenv\u3002<\/span><\/li>\n
    • putenv(pwdenv) \u628a\u8fd9\u4e2a\u5b57\u7b26\u4e32\u5199\u56de\u8fdb\u7a0b\u7684\u771f\u5b9e\u73af\u5883\u8868（\u6ce8\u610f：\u5199\u7684\u662f pwd \u91cc\u7684，\u4e0d\u662f genv，\u8fd9\u5c31\u662f\u540e\u9762\u7684\u5751\u4e4b\u4e00，\u8be6\u89c1\u7b2c\u516b\u8282）\u3002<\/span><\/li>\n<\/ul>\n\n\u7ef4\u5ea6<\/span>getcwd<\/span>getenv<\/span><\/tr>\n\n\n\n\n\n\n\n
      \u5934\u6587\u4ef6<\/span><\/td>\n<unistd.h><\/span><\/td>\n<stdlib.h><\/span><\/td>\n<\/tr>\n
      \u83b7\u53d6\u5bf9\u8c61<\/span><\/td>\n\u5f53\u524d\u5de5\u4f5c\u76ee\u5f55（\u7edd\u5bf9\u8def\u5f84）<\/span><\/td>\n\u73af\u5883\u53d8\u91cf\u7684\u503c<\/span><\/td>\n<\/tr>\n
      \u7ed3\u679c\u5b58\u54ea<\/span><\/td>\n\u4f60\u81ea\u5df1\u7684\u7f13\u51b2\u533a（\u6216\u52a8\u6001\u5206\u914d）<\/span><\/td>\n\u8fdb\u7a0b\u73af\u5883\u5757\u91cc\u7684\u5185\u90e8\u9759\u6001\u533a<\/span><\/td>\n<\/tr>\n
      \u8c01\u7ba1\u751f\u547d\u5468\u671f<\/span><\/td>\n\u8c03\u7528\u8005<\/span><\/td>\n\u8fdb\u7a0b\u73af\u5883（\u540e\u7eed\u8c03\u7528\u53ef\u80fd\u8986\u76d6）<\/span><\/td>\n<\/tr>\n
      \u5931\u8d25\u8868\u73b0<\/span><\/td>\n\u8fd4\u56de NULL + errno（ERANGE \u7f13\u51b2\u533a\u592a\u5c0f \/ EACCES \u65e0\u6743\u9650 \/ ENOENT \u76ee\u5f55\u88ab\u5220）<\/span><\/td>\n\u8fd4\u56de NULL，\u65e0 errno \u533a\u5206 "\u4e0d\u5b58\u5728"<\/span><\/td>\n<\/tr>\n
      \u5bf9\u5e94\u7684\u4fee\u6539\u51fd\u6570<\/span><\/td>\nchdir()<\/span><\/td>\nsetenv() \/ putenv()<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      LastDir：<\/span><\/p>\n

      \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u53d6\u6700\u540e\u4e00\u4e2a \/ \u540e\u9762\u7684\u90e8\u5206\u505a\u63d0\u793a\u7b26\u76ee\u5f55\u663e\u793a（\/home\/xx \u2192 xx）\u3002<\/span><\/p>\n

      \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0MakeCommandLine：\u62fc\u6210 [user@host dir]# \u3002<\/span><\/p>\n

      \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0PrintCommandLine：<\/span><\/p>\n

      printf("%s", MakeCommandLine().c_str());
      \nfflush(stdout); \/\/ \u5fc5\u987b fflush，\u56e0\u4e3a\u63d0\u793a\u7b26\u6ca1 \\\\n<\/p>\n

      \u8fd9\u662f\u96be\u70b9：<\/span><\/p>\n

      \u00a0\u00a0\u00a0\u00a0printf \u9ed8\u8ba4\u662f\u884c\u7f13\u51b2（\u6709 \\\\n \u624d\u771f\u6b63\u8f93\u51fa），\u63d0\u793a\u7b26\u6ca1\u6709\u6362\u884c，\u6240\u4ee5\u5fc5\u987b\u624b\u52a8 fflush，\u5426\u5219\u4f60\u8f93\u5165\u547d\u4ee4\u65f6\u63d0\u793a\u7b26\u8fd8\u618b\u5728\u7f13\u51b2\u533a\u91cc\u6ca1\u663e\u793a\u51fa\u6765\u3002<\/span><\/p>\n

      \n

      \u4e09\u3001GetCommandLine：\u8bfb\u4e00\u884c<\/span><\/h3>\n

      if (fgets(buf, size, stdin) == NULL) { printf("\\\\n"); return false; }
      \nbuf[strlen(buf) – 1] = '\\\\0'; \/\/ \u53bb\u6389 fgets \u8bfb\u8fdb\u6765\u7684 \\\\n
      \nif (strlen(buf) == 0) return false;<\/p>\n

        \n
      • fgets \u8bfb\u5230\u6362\u884c\u6216\u7f13\u51b2\u533a\u6ee1\u4e3a\u6b62，\u6362\u884c\u4f1a\u4fdd\u7559\u5728 buf \u91cc，\u6240\u4ee5\u8981\u624b\u52a8\u628a\u6700\u540e\u4e00\u4f4d（\\\\n）\u6362\u6210 '\\\\0'\u3002<\/span><\/li>\n
      • \u4e09\u4e2a\u8fd4\u56de\u503c\u8bed\u4e49：<\/span>\n
          \n
        • \u6b63\u5e38\u4e00\u884c \u2192 true<\/span><\/li>\n
        • \u7a7a\u884c（\u76f4\u63a5\u56de\u8f66，\u53bb \\\\n \u540e\u4e3a\u7a7a）\u2192 false，\u4e3b\u5faa\u73af continue \u91cd\u65b0\u6253\u5370\u63d0\u793a\u7b26<\/span><\/li>\n
        • EOF（Ctrl+D）\u2192 \u6253\u5370\u6362\u884c\u3001false\u2014\u2014\u8fd9\u91cc\u57cb\u4e86\u4e2a bug，\u89c1\u7b2c\u516b\u8282\u3002<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
          \n

          \u56db\u3001ParseCommandLine：strtok \u62c6\u8bcd（\u96be\u70b9\u2460）<\/span><\/h3>\n

          const char *sep = " ";
          \ngargv[gargc++] = strtok(buf, sep); \/\/ \u7b2c\u4e00\u6b21\u8c03\u7528\u4f20 buf
          \nwhile ((gargv[gargc++] = strtok(NULL, sep)) != NULL)
          \n ;
          \ngargc–;<\/p>\n

          strtok \u7684\u5de5\u4f5c\u539f\u7406（\u8fd9\u662f\u6700\u503c\u5f97\u6df1\u6316\u7684\u5730\u65b9）：<\/span><\/p>\n

        • \u7b2c\u4e00\u6b21\u8c03\u7528 strtok(buf, " ")：\u4ece buf \u5f00\u5934\u627e\u7b2c\u4e00\u4e2a\u975e\u7a7a\u683c\u5b57\u7b26，\u8bb0\u4e0b\u5355\u8bcd\u8d77\u70b9；\u518d\u4ece\u90a3\u91cc\u5f80\u540e\u627e\u7a7a\u683c，\u627e\u5230\u5c31\u628a\u7a7a\u683c\u66ff\u6362\u6210 '\\\\0'，\u8fd4\u56de\u5355\u8bcd\u8d77\u70b9\u6307\u9488\u3002\u540c\u65f6，strtok \u5185\u90e8\u7528\u4e00\u4e2a\u9759\u6001\u6307\u9488\u8bb0\u4f4f\u5f53\u524d\u4f4d\u7f6e（\u505c\u5728\u521a\u624d\u90a3\u4e2a '\\\\0' \u4e4b\u540e）\u3002<\/span><\/li>\n
        • \u540e\u7eed\u8c03\u7528 strtok(NULL, " ")：\u4e0d\u4f20\u65b0\u5b57\u7b26\u4e32，strtok \u4ece\u5185\u90e8\u8bb0\u4f4f\u7684\u4f4d\u7f6e\u7ee7\u7eed\u5207\u4e0b\u4e00\u4e2a\u5355\u8bcd\u3002<\/span><\/li>\n
        • \u8fde\u7eed\u7a7a\u683c\u81ea\u52a8\u8df3\u8fc7\u2014\u2014\u6240\u4ee5 ls -l \u548c ls -l \u7ed3\u679c\u4e00\u6837\u3002<\/span><\/li>\n
        • \u5b83\u76f4\u63a5\u4fee\u6539\u539f\u5b57\u7b26\u4e32：buf \u91cc\u7684\u7a7a\u683c\u88ab\u6539\u5199\u6210 '\\\\0'，\u4e8e\u662f buf \u88ab\u539f\u5730\u62c6\u6210\u597d\u51e0\u6bb5，gargv[i] \u53ea\u662f\u6307\u5411\u8fd9\u4e9b\u6bb5\u7684\u9996\u5730\u5740\u3002<\/span><\/li>\n

          \u4e3e\u4f8b：<\/span><\/p>\n

          \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u8f93\u5165 ls -l \/home，\u89e3\u6790\u540e\u5185\u5b58\u91cc\u662f ls\\\\0-l\\\\0\/home\\\\0，gargv = {"ls", "-l", "\/home", NULL}\u3002<\/span><\/p>\n

          \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u6700\u540e\u90a3\u4e2a gargc– \u662f\u56e0\u4e3a while \u5faa\u73af\u5728\u8d4b NULL \u4e4b\u540e\u53c8\u628a gargc \u52a0\u4e86\u4e00\u6b21（\u5faa\u73af\u6761\u4ef6\u5148\u8d4b\u503c\u540e\u5224\u65ad），\u6240\u4ee5\u8981\u591a\u9000\u4e00\u683c，\u4f46 NULL \u5df2\u7ecf\u5199\u8fdb\u6570\u7ec4\u2014\u2014\u8fd9\u6b63\u662f exec \u65cf\u9700\u8981\u7684\u7ed3\u5c3e\u6807\u8bb0\u3002<\/span><\/p>\n

          \u6f5c\u5728\u5d29\u6e83\u70b9：<\/span><\/p>\n

          \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u5982\u679c\u8f93\u5165\u662f\u7eaf\u7a7a\u683c（\u5982 " "），\u7b2c\u4e00\u4e2a strtok \u8fd4\u56de NULL，gargv[0]=NULL，\u540e\u9762 CheckAndExecBuiltCommand \u91cc strcmp(gargv[0], "exit") \u4f1a\u5bf9 NULL \u505a strcmp \u2192 \u6bb5\u9519\u8bef\u3002<\/span><\/p>\n

          \n

          \u4e94\u3001\u73af\u5883\u53d8\u91cf：InitEnv \/ AddEnv（\u96be\u70b9\u2461：\u4e09\u5957\u73af\u5883\u8868）<\/span><\/h3>\n

          \u8fd9\u4e2a\u7a0b\u5e8f\u91cc\u5176\u5b9e\u6709\u4e09\u5957\u73af\u5883，\u521d\u5b66\u8005\u6700\u5bb9\u6613\u6df7\u6dc6：<\/span><\/p>\n\n\u8868<\/span>\u662f\u8c01<\/span>\u600e\u4e48\u4ea7\u751f\u7684<\/span>\u8c01\u5728\u7528<\/span><\/tr>\n\n\n\n\n
          environ<\/span><\/td>\n\n

          \u5185\u6838 + libc \u7ef4\u62a4\u7684\u8fdb\u7a0b\u771f\u5b9e\u73af\u5883\u8868<\/span><\/p>\n

          （extern char **environ，\u4ee5 NULL \u7ed3\u5c3e）<\/span><\/p>\n<\/td>\n

          		\u8fdb\u7a0b\u542f\u52a8\u65f6\u7531 exec \u4f20\u5165<\/span><\/td>\ngetenv \/ putenv \u64cd\u4f5c\u5b83<\/span><\/td>\n<\/tr>\n
          genv<\/span><\/td>\nshell \u81ea\u5df1 malloc \u62f7\u8d1d\u7684\u4e00\u4efd<\/span><\/td>\nInitEnv \u4ece environ \u62f7\u8d1d，export \u8ffd\u52a0<\/span><\/td>\n\u4f20\u7ed9 execvpe \u7ed9\u5b50\u8fdb\u7a0b<\/span><\/td>\n<\/tr>\n
          pwdenv<\/span><\/td>\n\u5168\u5c40\u9759\u6001\u6570\u7ec4<\/span><\/td>\nGetPwd \u6bcf\u6b21\u62fc PWD=xxx \u5e76 putenv<\/span><\/td>\n\u53ea\u5199\u56de environ，\u4e0d\u8fdb genv<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          InitEnv：<\/span><\/p>\n

          extern char **environ; \/\/ \u58f0\u660e：\u8fdb\u7a0b\u771f\u5b9e\u73af\u5883\u8868
          \nfor (; environ[i] && i < envnum – 1; i++) {
          \n genv[i] = (char *)malloc(strlen(environ[i]) + 1);
          \n strcpy(genv[i], environ[i]);
          \n}
          \ngenv[i] = NULL;<\/p>\n

          \u4e3a\u4ec0\u4e48\u8981 malloc \u62f7\u8d1d\u800c\u4e0d\u662f\u76f4\u63a5 genv[i] = environ[i]？<\/span><\/p>\n

          \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u56e0\u4e3a putenv\u3001setenv \u53ef\u80fd\u4f1a\u79fb\u52a8\/\u6539\u5199 environ \u8868\u9879，\u62f7\u4e00\u4efd\u81ea\u5df1\u7684\u526f\u672c\u624d\u5b89\u5168\u3002\u8fd9\u4e2a shell \u540e\u7eed\u8981\u7ed9\u5b50\u8fdb\u7a0b\u4e00\u4efd"\u81ea\u5df1\u8bf4\u4e86\u7b97"\u7684\u73af\u5883（\u7528\u6237 export \u52a0\u8fdb\u53bb\u7684\u53d8\u91cf\u4e5f\u8981\u5728），\u6240\u4ee5\u5b83\u7ef4\u62a4\u81ea\u5df1\u7684 genv\u3002<\/span><\/p>\n

          AddEnv：<\/span><\/p>\n

          while (genv[i]) i++; \/\/ \u627e\u5230\u672b\u5c3e
          \ngenv[i] = malloc(strlen(item)+1);
          \nstrcpy(genv[i], item);
          \ngenv[++i] = NULL;<\/p>\n

          \u6ce8\u610f\u5b83\u6ca1\u6709\u68c0\u67e5 genv \u662f\u5426\u5df2\u6ee1 64 \u9879\u2014\u2014export \u8d85\u8fc7 64 \u6b21\u4f1a\u6570\u7ec4\u8d8a\u754c\u5199（\u5185\u5b58\u7834\u574f）\u3002<\/span><\/p>\n

          \n

          \u516d\u3001ExecuteCommand：fork \/ exec \/ waitpid（\u96be\u70b9\u2462，\u5168\u7a0b\u5e8f\u6838\u5fc3）<\/span><\/h3>\n

          pid_t id = fork();
          \nif (id < 0) { perror("fork"); lastcode = 1; return; }
          \nif (id == 0) {
          \n execvpe(gargv[0], gargv, genv); \/\/ \u5b50\u8fdb\u7a0b
          \n perror(gargv[0]); \/\/ exec \u5931\u8d25\u624d\u4f1a\u8d70\u5230\u8fd9
          \n exit(127);
          \n}
          \nint status = 0;
          \nwaitpid(id, &status, 0); \/\/ \u7236\u8fdb\u7a0b
          \nif (WIFEXITED(status))
          \n lastcode = WEXITSTATUS(status);
          \nelse if (WIFSIGNALED(status))
          \n lastcode = 128 + WTERMSIG(status);
          \nelse
          \n lastcode = 100;<\/p>\n

          \u2460 fork()：\u4e00\u6b21\u8c03\u7528，\u4e24\u6b21\u8fd4\u56de<\/span><\/p>\n

            \n
          • fork \u4f1a\u590d\u5236\u5f53\u524d\u8fdb\u7a0b（\u5199\u65f6\u62f7\u8d1d COW：\u4e0d\u4fee\u6539\u6570\u636e\u65f6\u7236\u5b50\u5171\u4eab\u7269\u7406\u5185\u5b58\u9875，\u8c01\u5148\u6539\u8c01\u590d\u5236），\u521b\u5efa\u5b50\u8fdb\u7a0b\u3002<\/span><\/li>\n
          • \u8fd4\u56de\u503c\u8bed\u4e49：\u7236\u8fdb\u7a0b\u5f97\u5230\u5b50\u8fdb\u7a0b\u7684 PID（>0）；\u5b50\u8fdb\u7a0b\u5f97\u5230 0；\u5931\u8d25\u5f97 -1\u3002<\/span><\/li>\n
          • \u5224\u65ad id == 0 \u5c31\u662f\u5728\u95ee"\u6211\u73b0\u5728\u662f\u4e0d\u662f\u5b50\u8fdb\u7a0b？"\u2014\u2014\u8fd9\u5c31\u662f fork \u540e\u7236\u5b50\u4ee3\u7801\u5206\u9053\u626c\u9573\u7684\u7ecf\u5178\u5199\u6cd5\u3002<\/span><\/li>\n<\/ul>\n

            \u2461 execvpe：exec \u5bb6\u65cf\u91cc\u529f\u80fd\u6700\u5168\u7684\u4e00\u4e2a execvpe(\u6587\u4ef6\u540d, argv, envp) \u62c6\u5f00\u770b：<\/span><\/p>\n

              \n
            • exec：\u7528\u65b0\u7a0b\u5e8f\u66ff\u6362\u5f53\u524d\u8fdb\u7a0b\u6620\u50cf\u2014\u2014\u4ee3\u7801\u6bb5\u3001\u6570\u636e\u6bb5\u3001\u5806\u6808\u5168\u6362，PID \u4e0d\u53d8\u3002<\/span><\/li>\n
            • v：\u53c2\u6570\u4ee5 char*[]（argv \u6570\u7ec4）\u4f20\u5165\u3002<\/span><\/li>\n
            • p：\u81ea\u52a8\u6309 PATH \u73af\u5883\u53d8\u91cf\u641c\u7d22\u53ef\u6267\u884c\u6587\u4ef6，\u6240\u4ee5\u4e0d\u7528\u5199 \/bin\/ls，\u5199 ls \u5c31\u884c\u3002<\/span><\/li>\n
            • e：\u7528\u81ea\u5b9a\u4e49\u73af\u5883 genv \u4f5c\u4e3a\u65b0\u7a0b\u5e8f\u7684\u73af\u5883\u8868（\u4e0d\u662f\u9ed8\u8ba4\u7684 environ）\u3002<\/span><\/li>\n<\/ul>\n

              \u5173\u952e：<\/span><\/p>\n

              \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0exec \u6210\u529f\u4e0d\u8fd4\u56de\u2014\u2014\u65b0\u7a0b\u5e8f\u8dd1\u8d77\u6765\u540e，"\u5b50\u8fdb\u7a0b"\u8fd9\u4e2a\u8eab\u4efd\u5c31\u53d8\u6210 ls \u8fdb\u7a0b\u4e86，perror \u548c exit(127) \u90a3\u4e24\u884c\u6c38\u8fdc\u4e0d\u4f1a\u6267\u884c；<\/span><\/p>\n

              \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u53ea\u6709 exec \u5931\u8d25（\u6bd4\u5982\u547d\u4ee4\u4e0d\u5b58\u5728）\u624d\u8fd4\u56de -1，\u6253\u5370\u9519\u8bef\u5e76 exit(127)\u3002<\/span><\/p>\n

              \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0127 \u662f shell \u7ea6\u5b9a："\u547d\u4ee4\u627e\u4e0d\u5230"\u3002<\/span><\/p>\n

              \u2462 waitpid：\u7236\u8fdb\u7a0b\u6536\u5c38<\/span><\/p>\n

                \n
              • waitpid(id, &status, 0) \u963b\u585e\u7b49\u5f85\u6307\u5b9a\u5b50\u8fdb\u7a0b\u7ed3\u675f，\u56de\u6536\u5176\u8d44\u6e90（\u50f5\u5c38\u8fdb\u7a0b\u56de\u6536）\u3002status \u662f\u4e00\u4e2a int，\u9000\u51fa\u4fe1\u606f\u88ab\u6253\u5305\u5728\u7279\u5b9a\u4f4d\u91cc，\u5fc5\u987b\u7528\u5b8f\u62c6\u5f00：<\/span>\n
                  \n
                • WIFEXITED(status)：\u662f\u5426\u6b63\u5e38\u9000\u51fa（\u8c03\u7528\u4e86 exit \/ main \u8fd4\u56de）\u2192 WEXITSTATUS \u53d6\u4f4e 8 \u4f4d\u9000\u51fa\u7801\u3002<\/span><\/li>\n
                • WIFSIGNALED(status)：\u662f\u5426\u88ab\u4fe1\u53f7\u6740\u6b7b（\u5982 kill\u3001Ctrl+C \u7684 SIGINT）\u2192 128 + WTERMSIG(status)，\u8fd9\u662f shell \u60ef\u4f8b：\u88ab 9 \u53f7\u4fe1\u53f7\u6740\u5c31\u662f 137\u3002<\/span><\/li>\n<\/ul>\n<\/li>\n
                • \u62c6\u51fa\u7684\u7ed3\u679c\u5b58\u8fdb\u5168\u5c40 lastcode，\u4f9b echo $? \u8bfb\u53d6\u3002<\/span><\/li>\n<\/ul>\n
                  \n

                  \u4e03\u3001\u5185\u5efa\u547d\u4ee4 CheckAndExecBuiltCommand<\/span><\/h3>\n

                  \u9010\u4e2a\u770b：<\/span><\/p>\n

                  exit：<\/span><\/p>\n

                  \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u76f4\u63a5 exit(0) \u7ec8\u6b62\u6574\u4e2a\u8fdb\u7a0b\u3002<\/span><\/p>\n

                  \u4e3a\u4ec0\u4e48 shell \u7684 exit \u5fc5\u987b\u662f\u5185\u5efa？<\/span><\/p>\n

                  \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u56e0\u4e3a\u5982\u679c\u662f\u5916\u90e8\u7a0b\u5e8f，exit \u53ea\u80fd\u7ed3\u675f\u90a3\u4e2a\u5b50\u8fdb\u7a0b，shell \u81ea\u5df1\u8fd8\u6d3b\u7740\u3002<\/span><\/p>\n

                  cd：<\/span><\/p>\n

                  if (gargc == 2) {
                  \n if (chdir(gargv[1]) != 0) perror("cd");
                  \n} else {
                  \n chdir(getenv("HOME") ? getenv("HOME") : "\/");
                  \n}
                  \nlastcode = 0;<\/p>\n

                  \u00a0 \u00a0chdir \u662f\u7cfb\u7edf\u8c03\u7528，\u53ea\u6539\u53d8\u5f53\u524d\u8fdb\u7a0b（shell）\u81ea\u5df1\u7684\u5de5\u4f5c\u76ee\u5f55\u2014\u2014\u8fd9\u4e5f\u662f\u5fc5\u987b\u5185\u5efa\u7684\u539f\u56e0：\u5916\u90e8\u5b50\u8fdb\u7a0b\u6539\u4e86\u76ee\u5f55\u8ddf shell \u65e0\u5173\u3002<\/span><\/p>\n

                  \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u6ce8\u610f lastcode = 0 \u65e0\u6761\u4ef6\u6267\u884c，chdir \u5931\u8d25\u4e5f\u662f 0（\u7f3a\u9677）\u3002<\/span><\/p>\n

                  export：<\/span><\/p>\n

                  \u00a0\u00a0AddEnv(gargv[1])，\u628a KEY=VALUE \u8ffd\u52a0\u8fdb genv \u8868\u3002<\/span><\/p>\n

                  \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u4e0b\u4e00\u8f6e fork \u51fa\u6765\u7684\u5b50\u8fdb\u7a0b\u5c31\u4f1a\u5e26\u4e0a\u8fd9\u4e2a\u53d8\u91cf\u2014\u2014\u8fd9\u5c31\u662f\u73af\u5883\u53d8\u91cf"\u7ee7\u627f"\u7684\u5b9e\u73b0\u3002<\/span><\/p>\n

                  env：\u904d\u5386\u6253\u5370 genv\u3002<\/span><\/p>\n

                  echo：<\/span><\/p>\n

                  if (gargc == 2) {
                  \n if (gargv[1][0] == '$' && gargv[1][1] == '?')
                  \n printf("%d\\\\n", lastcode);
                  \n else
                  \n printf("%s\\\\n", gargv[1]);
                  \n} else {
                  \n printf("\\\\n");
                  \n}<\/p>\n

                    \n
                  • echo $? \u5c31\u662f\u6253\u5370 lastcode\u3002<\/span><\/li>\n
                  • \u53ea\u652f\u6301\u5355\u4e2a\u53c2\u6570：echo a b c \u4f1a\u8d70 else \u53ea\u6253\u5370\u6362\u884c；echo $?x \u56e0\u4e3a\u7b2c\u4e8c\u4e2a\u5b57\u7b26\u662f ? \u4e5f\u4f1a\u88ab\u8bef\u5224\u6210 $?（\u7f3a\u9677）\u3002<\/span><\/li>\n<\/ul>\n
                    \n

                    \u516b\u3001main \u4e3b\u5faa\u73af + \u5df2\u77e5\u7f3a\u9677\u6e05\u5355<\/span><\/h3>\n

                    int main() {
                    \n InitEnv(); \/\/ \u542f\u52a8\u65f6\u5148\u62f7\u8d1d\u73af\u5883
                    \n char cmd[basesize];
                    \n while (true) {
                    \n PrintCommandLine();
                    \n if (!GetCommandLine(cmd, basesize)) continue;
                    \n ParseCommandLine(cmd);
                    \n if (CheckAndExecBuiltCommand()) continue;
                    \n ExecuteCommand();
                    \n }
                    \n}<\/p>\n

                    \u903b\u8f91\u94fe：\u63d0\u793a\u7b26 \u2192 \u8bfb \u2192 \u89e3\u6790 \u2192 \u5185\u5efa？\u2192 \u662f：continue \u56de\u5230\u9876\u90e8；\u5426：fork \u6267\u884c\u5916\u90e8\u547d\u4ee4 \u2192 \u56de\u5230\u9876\u90e8\u3002<\/span><\/p>\n

                    \u8fd9\u4e2a\u6559\u5b66\u7248\u4ee3\u7801\u91cc\u9690\u85cf\u7740\u51e0\u4e2a\u771f\u5b9e\u7f3a\u9677，\u503c\u5f97\u4f60\u77e5\u9053（\u9762\u8bd5\u5e38\u88ab\u95ee）：<\/span><\/p>\n\n#<\/span>\u7f3a\u9677<\/span>\u539f\u56e0<\/span>\u540e\u679c<\/span><\/tr>\n\n\n\n\n\n\n\n\n
                    1<\/span><\/td>\nCtrl+D \u6b7b\u5faa\u73af<\/span><\/td>\nEOF \u65f6 GetCommandLine \u8fd4\u56de false，main \u91cc\u5374 continue \u56de\u5230\u5faa\u73af\u9876\u90e8，\u4e0b\u4e00\u6b21 fgets \u53c8 EOF<\/span><\/td>\n\u5237\u5c4f\u6b7b\u5faa\u73af，Ctrl+D \u6839\u672c\u9000\u4e0d\u51fa\u53bb（\u5e94\u6539\u4e3a break \u6216\u533a\u5206 EOF\/\u7a7a\u884c）<\/span><\/td>\n<\/tr>\n
                    2<\/span><\/td>\n\u7eaf\u7a7a\u683c\u8f93\u5165\u6bb5\u9519\u8bef<\/span><\/td>\nstrtok \u8fd4\u56de NULL，gargv[0]=NULL，\u968f\u540e strcmp(NULL,…)<\/span><\/td>\n\u76f4\u63a5\u5d29<\/span><\/td>\n<\/tr>\n
                    3<\/span><\/td>\nPWD \u4e0d\u540c\u6b65<\/span><\/td>\nGetPwd \u7528 putenv \u66f4\u65b0\u7684\u662f\u771f\u5b9e environ，\u800c\u4f20\u7ed9\u5b50\u8fdb\u7a0b\u7684\u662f genv（\u542f\u52a8\u65f6\u62f7\u8d1d\u7684\u65e7\u503c）<\/span><\/td>\ncd \u4e4b\u540e\u5916\u90e8\u547d\u4ee4\u770b\u5230\u7684 $PWD \u4ecd\u662f shell \u542f\u52a8\u65f6\u7684\u503c<\/span><\/td>\n<\/tr>\n
                    4<\/span><\/td>\nargv \u6ea2\u51fa<\/span><\/td>\nParseCommandLine \u4e0d\u68c0\u67e5 gargc < argvnum<\/span><\/td>\n\u8d85 64 \u4e2a\u53c2\u6570\u8d8a\u754c\u5199<\/span><\/td>\n<\/tr>\n
                    5<\/span><\/td>\nexport \u8d8a\u754c<\/span><\/td>\nAddEnv \u4e0d\u68c0\u67e5 genv \u5bb9\u91cf<\/span><\/td>\nexport \u8d85 64 \u6b21\u8d8a\u754c\u5199<\/span><\/td>\n<\/tr>\n
                    6<\/span><\/td>\necho a b c \u53ea\u8f93\u51fa\u7a7a\u884c<\/span><\/td>\necho \u53ea\u5904\u7406 gargc==2<\/span><\/td>\n\u591a\u53c2\u6570\u88ab\u541e<\/span><\/td>\n<\/tr>\n
                    7<\/span><\/td>\ncd \u5931\u8d25\u4e5f lastcode=0<\/span><\/td>\nlastcode = 0 \u65e0\u6761\u4ef6\u6267\u884c<\/span><\/td>\n$? \u4e0d\u53cd\u6620\u771f\u5b9e\u5931\u8d25<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
                    \n

                    \u4e5d\u3001\u7f16\u8bd1\u6ce8\u610f<\/span><\/h3>\n
                      \n
                    • \u7f16\u8bd1\u547d\u4ee4：g++ -o mini_shell mini_shell.cpp -std=c++11<\/span><\/li>\n
                    • execvpe \u662f GNU \u6269\u5c55，\u58f0\u660e\u5728 unistd.h \u7684 #ifdef __USE_GNU \u5757\u91cc\u3002\u5982\u679c\u7f16\u8bd1\u62a5 execvpe was not declared，\u9700\u8981\u52a0\u5b8f：g++ -o mini_shell mini_shell.cpp -std=c++11 -D_GNU_SOURCE<\/span><\/li>\n
                    • \u5b83\u4f9d\u8d56 Linux\/Unix \u73af\u5883（fork\/exec\/waitpid \u90fd\u662f POSIX \u7cfb\u7edf\u8c03\u7528），Windows \u4e0a\u65e0\u6cd5\u76f4\u63a5\u7f16\u8bd1\u8fd0\u884c\u3002<\/span><\/li>\n<\/ul>\n

                      \u5341\u3001\u51fd\u6570\u590d\u4e60<\/span><\/h3>\n

                      C \u8bed\u8a00 `<string.h>` \u4e2d\u4ee5 `str` \u5f00\u5934\u7684\u51fd\u6570（C \u98ce\u683c\u5b57\u7b26\u4e32）：<\/p>\n

                      \u8868\u683c<\/p>\n

                      | \u51fd\u6570 | \u4f5c\u7528 |
                      \n| — | — |
                      \n| `strlen(s)` | \u6c42\u957f\u5ea6（\u4e0d\u542b `\\\\0`） |
                      \n| `strcpy(dest, src)` | \u590d\u5236\u5b57\u7b26\u4e32（\u4e0d\u68c0\u67e5\u5bb9\u91cf，\u5371\u9669） |
                      \n| `strncpy(dest, src, n)` | \u590d\u5236\u6700\u591a n \u4e2a\u5b57\u7b26 |
                      \n| `strcat(dest, src)` | \u62fc\u63a5（\u4e0d\u68c0\u67e5\u5bb9\u91cf，\u5371\u9669） |
                      \n| `strncat(dest, src, n)` | \u62fc\u63a5\u6700\u591a n \u4e2a\u5b57\u7b26 |
                      \n| `strcmp(s1, s2)` | \u6bd4\u8f83（<0\u30010\u3001>0） |
                      \n| `strncmp(s1, s2, n)` | \u6bd4\u8f83\u524d n \u4e2a\u5b57\u7b26 |
                      \n| `strchr(s, c)` | \u6b63\u5411\u627e\u5b57\u7b26，\u8fd4\u56de\u6307\u9488，\u627e\u4e0d\u5230\u8fd4\u56de `NULL` |
                      \n| `strrchr(s, c)` | \u53cd\u5411\u627e\u5b57\u7b26 |
                      \n| `strstr(s, sub)` | \u627e\u5b50\u4e32，\u8fd4\u56de\u5b50\u4e32\u9996\u5730\u5740\u6307\u9488 |
                      \n| `strtok(s, delim)` | \u6309\u5206\u9694\u7b26\u5207\u5206\u5b57\u7b26\u4e32 |
                      \n| `strdup(s)` | \u590d\u5236\u4e00\u4efd\u65b0\u5b57\u7b26\u4e32（\u9700 `free`） |
                      \n| `strspn(s, accept)` | \u8fd4\u56de s \u5f00\u5934\u8fde\u7eed\u5c5e\u4e8e accept \u7684\u5b57\u7b26\u6570 |
                      \n| `strcspn(s, reject)` | \u8fd4\u56de s \u5f00\u5934\u8fde\u7eed\u4e0d\u5c5e\u4e8e reject \u7684\u5b57\u7b26\u6570 |
                      \n| `strerror(errno)` | \u628a\u9519\u8bef\u7801\u8f6c\u6210\u9519\u8bef\u4fe1\u606f\u5b57\u7b26\u4e32 |<\/p>\n

                      \u5e38\u7528\u793a\u4f8b：<\/p>\n

                      ```
                      \n#include <string.h><\/p>\n

                      char s1[] = "hello";
                      \nchar s2[20];<\/p>\n

                      strcpy(s2, s1); \/\/ s2 = "hello"
                      \nstrcat(s2, " world"); \/\/ s2 = "hello world"<\/p>\n

                      if (strcmp(s1, "hello") == 0) { \/\/ \u76f8\u7b49
                      \n}<\/p>\n

                      char *p = strstr(s2, "wor"); \/\/ \u6307\u5411 "world" \u5f00\u5934
                      \nchar *c = strchr(s2, 'o'); \/\/ \u6307\u5411\u7b2c\u4e00\u4e2a 'o'<\/p>\n

                      \/\/ strtok \u5207\u5206
                      \nchar s[] = "apple,banana,cherry";
                      \nchar *tok = strtok(s, ",");
                      \nwhile (tok) {
                      \n printf("%s\\\\n", tok); \/\/ apple \/ banana \/ cherry
                      \n tok = strtok(NULL, ",");
                      \n}
                      \n```<\/p>\n\n\u51fd\u6570<\/span>\u8f93\u51fa\u76ee\u6807<\/span>\u5b89\u5168\u7248\u672c<\/span>\u8bf4\u660e<\/span><\/tr>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
                      printf<\/span><\/td>\n\u6807\u51c6\u8f93\u51fa<\/span><\/td>\n\u2014<\/span><\/td>\n\u6700\u5e38\u7528<\/span><\/td>\n<\/tr>\n
                      fprintf<\/span><\/td>\n\u6307\u5b9a\u6587\u4ef6\u6d41<\/span><\/td>\n\u2014<\/span><\/td>\nfprintf(stderr, …) \u6253\u9519\u8bef<\/span><\/td>\n<\/tr>\n
                      sprintf<\/span><\/td>\n\u5b57\u7b26\u7f13\u51b2\u533a<\/span><\/td>\nsprintf_s<\/span><\/td>\n\u4e0d\u68c0\u67e5\u5bb9\u91cf，\u4f1a\u6ea2\u51fa，\u614e\u7528<\/span><\/td>\n<\/tr>\n
                      snprintf<\/span><\/td>\n\u5b57\u7b26\u7f13\u51b2\u533a（\u9650\u957f）<\/span><\/td>\nsnprintf_s<\/span><\/td>\n\u63a8\u8350，\u5b89\u5168<\/span><\/td>\n<\/tr>\n
                      asprintf<\/span><\/td>\n\u81ea\u52a8\u5206\u914d\u7f13\u51b2\u533a<\/span><\/td>\n\u2014<\/span><\/td>\nGNU \u6269\u5c55，\u81ea\u52a8 malloc，\u9700 free<\/span><\/td>\n<\/tr>\n
                      dprintf<\/span><\/td>\n\u6587\u4ef6\u63cf\u8ff0\u7b26 fd<\/span><\/td>\n\u2014<\/span><\/td>\nPOSIX，\u76f4\u63a5\u5199 fd<\/span><\/td>\n<\/tr>\n
                      sprintf_s<\/span><\/td>\n\u5b57\u7b26\u7f13\u51b2\u533a<\/span><\/td>\n\u2014<\/span><\/td>\nMSVC \u5b89\u5168\u7248，\u9a8c\u8bc1\u53c2\u6570<\/span><\/td>\n<\/tr>\n
                      snprintf_s<\/span><\/td>\n\u5b57\u7b26\u7f13\u51b2\u533a（\u9650\u957f）<\/span><\/td>\n\u2014<\/span><\/td>\nMSVC \u5b89\u5168\u7248<\/span><\/td>\n<\/tr>\n
                      vprintf<\/span><\/td>\n\u6807\u51c6\u8f93\u51fa<\/span><\/td>\n\u2014<\/span><\/td>\n\u63a5\u53d7 va_list<\/span><\/td>\n<\/tr>\n
                      vfprintf<\/span><\/td>\n\u6587\u4ef6\u6d41<\/span><\/td>\n\u2014<\/span><\/td>\n\u63a5\u53d7 va_list<\/span><\/td>\n<\/tr>\n
                      vsprintf<\/span><\/td>\n\u7f13\u51b2\u533a<\/span><\/td>\nvsprintf_s<\/span><\/td>\n\u4e0d\u68c0\u67e5\u5bb9\u91cf<\/span><\/td>\n<\/tr>\n
                      vsnprintf<\/span><\/td>\n\u7f13\u51b2\u533a（\u9650\u957f）<\/span><\/td>\nvsnprintf_s<\/span><\/td>\n\u63a5\u53d7 va_list \u7684 snprintf<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                      \u7248\u672c\u4e00：C\u8bed\u8a00<\/span><\/h2>\n

                      #include "myshell.h"<\/p>\n

                      #include <stdlib.h>
                      \n#include <string.h>
                      \n#include <unistd.h>
                      \n#include <sys\/stat.h>
                      \n#include <sys\/wait.h><\/p>\n

                      \/\/ \u63d0\u793a\u7b26(\u771f\u7684\u662f\u5b57\u7b26\u4e32)\u76f8\u5173
                      \nstatic char username[32];
                      \nstatic char hostname[64];
                      \nstatic char cwd[256];
                      \nstatic char commandline[256];<\/p>\n

                      \/\/ \u547d\u4ee4\u884c\u76f8\u5173
                      \nstatic char *argv[64]; \/\/ \u4e00\u822c\u6700\u591a\u4e5f\u5c31\u5341\u51e0\u4e2a
                      \nstatic int argc = 0;
                      \nstatic const char *sep = " ";<\/p>\n

                      \/\/ \u4e0e\u9000\u51fa\u7801\u6709\u5173
                      \nstatic int lastcode;<\/p>\n

                      \/\/ \u4e0e\u73af\u5883\u53d8\u91cf\u6709\u5173，\u5e94\u8be5\u7531bash\u6765\u7ef4\u62a4，\u4ece\u7cfb\u7edf\u914d\u7f6e\u6587\u4ef6\u8bfb，\u76f4\u63a5\u4ece\u7cfb\u7edfbash\u62f7\u8d1d\u5373\u53ef
                      \nstatic char *env[64];<\/p>\n

                      static void GetUserName()
                      \n{
                      \n char *_username = getenv("USER"); \/\/ \u83b7\u53d6\u73af\u5883\u53d8\u91cf
                      \n strcpy(username,(_username ? _username : "None"));
                      \n}<\/p>\n

                      static void GetHostName()
                      \n{
                      \n char *_hostname = getenv("HOSTNAME"); \/\/ \u83b7\u53d6\u73af\u5883\u53d8\u91cf
                      \n strcpy(hostname,(_hostname ? _hostname : "None"));
                      \n}<\/p>\n

                      \/\/static void GetCwdName() \/\/ \u8981\u8be6\u7ec6\u5904\u7406，\u5305\u62ec\u53ea\u4fdd\u7559"\/"\u4e4b\u540e\u7684\u8def\u5f84
                      \n\/\/{
                      \n\/\/ char *_cwd = getenv("PWD"); \/\/ \u83b7\u53d6\u73af\u5883\u53d8\u91cf
                      \n\/\/ strcpy(cwd,(_cwd ? _cwd : "None"));
                      \n\/\/}<\/p>\n

                      static void GetCwdName() \/\/ \u8981\u8be6\u7ec6\u5904\u7406，\u5305\u62ec\u53ea\u4fdd\u7559"\/"\u4e4b\u540e\u7684\u8def\u5f84
                      \n{
                      \n char _cwd[256];
                      \n getcwd(_cwd,sizeof(_cwd));
                      \n if(strcmp(_cwd,"\/") == 0)
                      \n {
                      \n strcpy(cwd,_cwd);
                      \n }
                      \n else
                      \n {
                      \n int end = strlen(_cwd) – 1;
                      \n while(end >= 0)
                      \n {
                      \n if(_cwd[end] == '\/')
                      \n {
                      \n \/\/ \u5982 \/home\/Alice
                      \n strcpy(cwd,&_cwd[end + 1]);
                      \n break;
                      \n }
                      \n end–;
                      \n }
                      \n }
                      \n}<\/p>\n

                      void PrintPrompt()
                      \n{
                      \n GetUserName();
                      \n GetHostName();
                      \n GetCwdName();
                      \n printf("[%s@%s %s]# ",username,hostname,cwd);
                      \n fflush(stdout); \/\/ \u76f4\u63a5\u5237\u65b0\u7f13\u51b2\u533a
                      \n}<\/p>\n

                      static void GetCommandLine()
                      \n{
                      \n if(fgets(commandline,sizeof(commandline),stdin) != NULL)
                      \n {
                      \n \/\/ \u6bd4\u5982"abcd\\\\n" -> "abcd"
                      \n commandline[strlen(commandline) – 1] = 0;
                      \n \/\/ printf("debug:%s\\\\n",commandline);
                      \n }
                      \n}<\/p>\n

                      static void ParseCommandLine()
                      \n{
                      \n \/\/ \u6e05\u7a7a
                      \n argc = 0;
                      \n memset(argv,0,sizeof(argv));
                      \n \/\/ \u5224\u7a7a
                      \n if(strlen(commandline) == 0)
                      \n return;
                      \n \/\/ \u89e3\u6790 ls -a -l
                      \n argv[argc] = strtok(commandline,sep); \/\/ strtok\u5206\u5272\u5b57\u7b26\u4e32，\u53d8\u6210\u51e0\u4e2a\u5b50\u4e32
                      \n while((argv[++argc] = strtok(NULL,sep))); \/\/ argc\u7684\u5927\u5c0f\u5373\u5b50\u4e32\u4e2a\u6570<\/p>\n

                      \/\/ \/\/ \u8c03\u8bd5\u4fe1\u606f\u6ce8\u91ca\u6389
                      \n\/\/ printf("argc:%d\\\\n",argc);
                      \n\/\/ int i = 0;
                      \n\/\/ for(;argv[i];i++)
                      \n\/\/ {
                      \n\/\/ printf("argv[%d]:%s\\\\n",i,argv[i]);
                      \n\/\/ }
                      \n}<\/p>\n

                      \/\/ \u521b\u5efa\u5b50\u8fdb\u7a0b
                      \nvoid Execute()
                      \n{
                      \n pid_t id = fork();
                      \n if(id < 0)
                      \n {
                      \n perror("fork");
                      \n return;
                      \n }
                      \n else if(id == 0)
                      \n {
                      \n \/\/ printf("child running..\\\\n");
                      \n \/\/ \u5b50\u8fdb\u7a0b
                      \n \/\/ \u7a0b\u5e8f\u66ff\u6362
                      \n execvp(argv[0],argv);
                      \n exit(1);
                      \n }
                      \n else{
                      \n \/\/ \u7236\u8fdb\u7a0b
                      \n int status = 0;
                      \n pid_t rid = waitpid(id,&status,0); \/\/ \u5f97\u5230\u72b6\u6001
                      \n (void)rid;
                      \n lastcode = WEXITSTATUS(status);
                      \n }
                      \n}<\/p>\n

                      \/\/ 1：yes
                      \n\/\/ 0：no
                      \nint CheckBuiltinAndExcute()
                      \n{
                      \n int ret = 0;
                      \n if(strcmp(argv[0],"cd") == 0)
                      \n {
                      \n \/\/ \u5185\u5efa\u547d\u4ee4
                      \n ret = 1;
                      \n if(argc == 2) \/\/ \u6709\u9009\u9879
                      \n {
                      \n chdir(argv[1]);
                      \n }
                      \n }
                      \n else if(strcmp(argv[0],"echo") == 0)
                      \n {
                      \n ret = 1;
                      \n if(argc == 2)
                      \n {
                      \n \/\/ echo $?
                      \n \/\/ echo $PATH
                      \n \/\/ echo "helloworld"
                      \n \/\/ echo helloworld
                      \n if(argv[1][0] == '$')
                      \n {
                      \n if(strcmp(argv[1],"$?") == 0)
                      \n {
                      \n printf("%d\\\\n",lastcode);
                      \n lastcode = 0; \/\/ \u8fd4\u56de\u4e0a\u4e00\u6b21\u7684\u9000\u51fa\u7801
                      \n }
                      \n else
                      \n {
                      \n \/\/ env：\u73af\u5883\u53d8\u91cf
                      \n }
                      \n }
                      \n else
                      \n {
                      \n printf("%s\\\\n",argv[1]); \/\/ \u6253\u5370\u5b57\u7b26\u4e32，\u4e0d\u7ec6\u5206\u4ec0\u4e48""\u6216\u8005\u6ca1\u6709""\u4e86
                      \n }
                      \n }
                      \n }<\/p>\n

                      return ret;
                      \n}<\/p>\n

                      void Bash()
                      \n{
                      \n while(1) \/\/ \u8f6f\u4ef6\u90fd\u662f\u6b7b\u5faa\u73af\u7684
                      \n {
                      \n \/\/ \u7b2c1\u6b65：\u8f93\u51fa\u547d\u4ee4\u884c
                      \n PrintPrompt();<\/p>\n

                      \/\/ \u7b2c2\u6b65：\u7b49\u5f85\u7528\u6237\u8f93\u5165，\u83b7\u53d6\u7528\u6237\u8f93\u5165
                      \n \/\/ char commandline[256]; -> scanf()
                      \n \/\/ sleep(1); \/\/ \u7b49\u5f85\u4e00\u4f1a\u513f
                      \n GetCommandLine();<\/p>\n

                      \/\/ \u7b2c3\u6b65：\u89e3\u6790\u5b57\u7b26\u4e32，"ls -a -l" -> "ls" "-a" "-l"
                      \n ParseCommandLine();
                      \n if(argc == 0)
                      \n continue;<\/p>\n

                      \/\/ \u7b2c4\u6b65：\u6709\u4e9b\u547d\u4ee4，cd\u3001ench\u3001env\u3001export\u7b49\u547d\u4ee4，\u4e0d\u5e94\u8be5\u8ba9\u5b50\u8fdb\u7a0b\u6267\u884c，\u800c\u5e94\u8be5\u8ba9\u7236\u8fdb\u7a0b\u81ea\u5df1\u6267\u884c，\u5185\u5efa\u547d\u4ee4\u3002bash\u5185\u90e8\u7684\u51fd\u6570
                      \n if(CheckBuiltinAndExcute())
                      \n {
                      \n continue;
                      \n }<\/p>\n

                      \/\/ \u7b2c5\u6b65：\u6267\u884c\u547d\u4ee4
                      \n Execute();
                      \n }
                      \n}<\/p>\n

                      \u7248\u672c\u4e8c：C++<\/span><\/h2>\n

                      \/******************************************************************************
                      \n * mini_shell.cpp
                      \n * \u4e00\u4e2a\u6700\u5c0f\u53ef\u7528\u7684 Linux Shell：
                      \n * – \u652f\u6301\u666e\u901a\u5916\u90e8\u547d\u4ee4（ls \/ ps \/ whoami \/ pwd …）
                      \n * – \u652f\u6301\u5185\u5efa\u547d\u4ee4：cd \/ export \/ env \/ echo $? \/ exit
                      \n * – \u652f\u6301\u73af\u5883\u53d8\u91cf\u7ee7\u627f\u4e0e\u7ef4\u62a4
                      \n * – \u652f\u6301 echo $? \u6253\u5370\u4e0a\u4e00\u6761\u547d\u4ee4\u9000\u51fa\u7801
                      \n * \u7f16\u8bd1：g++ -o mini_shell mini_shell.cpp -std=c++11
                      \n * \u8fd0\u884c：.\/mini_shell
                      \n *****************************************************************************\/<\/p>\n

                      #include <iostream>
                      \n#include <cstdio>
                      \n#include <cstdlib>
                      \n#include <cstring>
                      \n#include <string>
                      \n#include <unistd.h>
                      \n#include <sys\/types.h>
                      \n#include <sys\/wait.h>
                      \n#include <ctype.h>
                      \nusing namespace std;<\/p>\n

                      \/* ====================== \u5168\u5c40\u914d\u7f6e ====================== *\/
                      \nconst int basesize = 1024; \/\/ \u547d\u4ee4\u884c\u7f13\u51b2\u533a\u5927\u5c0f
                      \nconst int argvnum = 64; \/\/ argv \u6700\u591a\u53c2\u6570\u4e2a\u6570
                      \nconst int envnum = 64; \/\/ \u73af\u5883\u53d8\u91cf\u6700\u591a\u4e2a\u6570<\/p>\n

                      \/* ====================== \u5168\u5c40\u72b6\u6001 ====================== *\/
                      \nstatic char *gargv[argvnum]; \/\/ \u547d\u4ee4\u884c\u53c2\u6570\u8868，\u672b\u5c3e\u5fc5\u987b\u4e3a NULL
                      \nstatic int gargc = 0; \/\/ \u53c2\u6570\u4e2a\u6570<\/p>\n

                      static int lastcode = 0; \/\/ \u4e0a\u4e00\u6761\u547d\u4ee4\u7684\u9000\u51fa\u7801（echo $? \u7528）<\/p>\n

                      static char *genv[envnum]; \/\/ shell \u81ea\u5df1\u7ef4\u62a4\u7684\u73af\u5883\u53d8\u91cf\u8868<\/p>\n

                      static char pwd[basesize]; \/\/ \u5f53\u524d\u5de5\u4f5c\u76ee\u5f55
                      \nstatic char pwdenv[basesize];\/\/ "PWD=xxx" \u5b57\u7b26\u4e32<\/p>\n

                      \/* ====================== \u63d0\u793a\u7b26\u76f8\u5173 ====================== *\/
                      \nstatic string GetUserName() {
                      \n const char *name = getenv("USER");
                      \n return name ? name : "None";
                      \n}<\/p>\n

                      static string GetHostName() {
                      \n const char *host = getenv("HOSTNAME");
                      \n return host ? host : "None";
                      \n}<\/p>\n

                      static string GetPwd() {
                      \n if (getcwd(pwd, sizeof(pwd)) == NULL) return "None";
                      \n snprintf(pwdenv, sizeof(pwdenv), "PWD=%s", pwd);
                      \n putenv(pwdenv);
                      \n return pwd;
                      \n}<\/p>\n

                      static string LastDir() {
                      \n string curr = GetPwd();
                      \n if (curr == "\/" || curr == "None") return curr;
                      \n size_t pos = curr.rfind("\/");
                      \n if (pos == string::npos) return curr;
                      \n return curr.substr(pos + 1);
                      \n}<\/p>\n

                      static string MakeCommandLine() {
                      \n char line[basesize];
                      \n snprintf(line, basesize, "[%s@%s %s]# ",
                      \n GetUserName().c_str(),
                      \n GetHostName().c_str(),
                      \n LastDir().c_str());
                      \n return line;
                      \n}<\/p>\n

                      static void PrintCommandLine() {
                      \n printf("%s", MakeCommandLine().c_str());
                      \n fflush(stdout); \/\/ \u5fc5\u987b fflush，\u56e0\u4e3a\u63d0\u793a\u7b26\u6ca1 \\\\n
                      \n}<\/p>\n

                      \/* ====================== \u8bfb\u547d\u4ee4\u884c ====================== *\/
                      \nstatic bool GetCommandLine(char buf[], int size) {
                      \n if (fgets(buf, size, stdin) == NULL) {
                      \n printf("\\\\n"); \/\/ Ctrl+D \u9000\u51fa
                      \n return false;
                      \n }
                      \n buf[strlen(buf) – 1] = '\\\\0'; \/\/ \u53bb\u6389 fgets \u8bfb\u8fdb\u6765\u7684 \\\\n
                      \n if (strlen(buf) == 0) return false;
                      \n return true;
                      \n}<\/p>\n

                      \/* ====================== \u89e3\u6790\u547d\u4ee4\u884c ====================== *\/
                      \nstatic void ParseCommandLine(char buf[]) {
                      \n memset(gargv, 0, sizeof(gargv));
                      \n gargc = 0;
                      \n const char *sep = " ";
                      \n gargv[gargc++] = strtok(buf, sep);
                      \n while ((gargv[gargc++] = strtok(NULL, sep)) != NULL)
                      \n ;
                      \n gargc–;
                      \n}<\/p>\n

                      \/* ====================== \u73af\u5883\u53d8\u91cf\u64cd\u4f5c ====================== *\/
                      \nstatic void InitEnv() {
                      \n extern char **environ;
                      \n int i = 0;
                      \n for (; environ[i] && i < envnum – 1; i++) {
                      \n genv[i] = (char *)malloc(strlen(environ[i]) + 1);
                      \n strcpy(genv[i], environ[i]);
                      \n }
                      \n genv[i] = NULL;
                      \n}<\/p>\n

                      static void AddEnv(const char *item) {
                      \n int i = 0;
                      \n while (genv[i]) i++;
                      \n genv[i] = (char *)malloc(strlen(item) + 1);
                      \n strcpy(genv[i], item);
                      \n genv[++i] = NULL;
                      \n}<\/p>\n

                      \/* ====================== \u5916\u90e8\u547d\u4ee4\u6267\u884c ====================== *\/
                      \nstatic void ExecuteCommand() {
                      \n pid_t id = fork();
                      \n if (id < 0) { perror("fork"); lastcode = 1; return; }<\/p>\n

                      if (id == 0) {
                      \n \/\/ \u5b50\u8fdb\u7a0b：\u66ff\u6362\u6210\u5916\u90e8\u7a0b\u5e8f
                      \n execvpe(gargv[0], gargv, genv);
                      \n perror(gargv[0]); \/\/ exec \u5931\u8d25\u624d\u4f1a\u8d70\u5230\u8fd9
                      \n exit(127);
                      \n }<\/p>\n

                      \/\/ \u7236\u8fdb\u7a0b：\u963b\u585e\u7b49\u5b50\u8fdb\u7a0b
                      \n int status = 0;
                      \n waitpid(id, &status, 0);<\/p>\n

                      if (WIFEXITED(status))
                      \n lastcode = WEXITSTATUS(status);
                      \n else if (WIFSIGNALED(status))
                      \n lastcode = 128 + WTERMSIG(status); \/\/ \u88ab\u4fe1\u53f7\u6740
                      \n else
                      \n lastcode = 100;
                      \n}<\/p>\n

                      \/* ====================== \u5185\u5efa\u547d\u4ee4 ====================== *\/
                      \nstatic bool CheckAndExecBuiltCommand() {
                      \n \/* exit：\u9000\u51fa shell *\/
                      \n if (strcmp(gargv[0], "exit") == 0) { printf("bye~\\\\n"); exit(0); }<\/p>\n

                      \/* cd：\u6539 shell \u81ea\u5df1\u7684\u5de5\u4f5c\u76ee\u5f55 *\/
                      \n if (strcmp(gargv[0], "cd") == 0) {
                      \n if (gargc == 2) {
                      \n if (chdir(gargv[1]) != 0) perror("cd");
                      \n } else {
                      \n chdir(getenv("HOME") ? getenv("HOME") : "\/");
                      \n }
                      \n lastcode = 0;
                      \n return true;
                      \n }<\/p>\n

                      \/* export KEY=VALUE *\/
                      \n if (strcmp(gargv[0], "export") == 0) {
                      \n if (gargc == 2) { AddEnv(gargv[1]); lastcode = 0; }
                      \n else lastcode = 1;
                      \n return true;
                      \n }<\/p>\n

                      \/* env：\u5217\u73af\u5883\u53d8\u91cf *\/
                      \n if (strcmp(gargv[0], "env") == 0) {
                      \n for (int i = 0; genv[i]; i++) printf("%s\\\\n", genv[i]);
                      \n lastcode = 0;
                      \n return true;
                      \n }<\/p>\n

                      \/* echo：\u652f\u6301 echo $? \/ echo xxx *\/
                      \n if (strcmp(gargv[0], "echo") == 0) {
                      \n if (gargc == 2) {
                      \n if (gargv[1][0] == '$' && gargv[1][1] == '?')
                      \n printf("%d\\\\n", lastcode);
                      \n else
                      \n printf("%s\\\\n", gargv[1]);
                      \n } else {
                      \n printf("\\\\n");
                      \n }
                      \n lastcode = 0;
                      \n return true;
                      \n }<\/p>\n

                      return false; \/\/ \u4e0d\u662f\u5185\u5efa，\u53bb fork
                      \n}<\/p>\n

                      \/* ====================== \u4e3b\u5faa\u73af ====================== *\/
                      \nint main() {
                      \n InitEnv();
                      \n char cmd[basesize];<\/p>\n

                      while (true) {
                      \n PrintCommandLine();
                      \n if (!GetCommandLine(cmd, basesize)) continue;
                      \n ParseCommandLine(cmd);
                      \n if (CheckAndExecBuiltCommand()) continue;
                      \n ExecuteCommand();
                      \n }
                      \n return 0;
                      \n}<\/p>\n

                      \u00a0\u00a0WIFEXITED \u662f <sys\/wait.h> \u4e2d\u7684\u5b8f，\u5224\u65ad\u5b50\u8fdb\u7a0b\u662f\u5426\u6b63\u5e38\u9000\u51fa（\u901a\u8fc7 exit() \u6216 return），\u914d\u5408 wait() \/ waitpid() \u4f7f\u7528：<\/span><\/p>\n

                      #include <sys\/wait.h>
                      \n#include <unistd.h>
                      \n#include <stdio.h><\/p>\n

                      pid_t pid = fork();
                      \nif (pid == 0) {
                      \n exit(42); \/\/ \u5b50\u8fdb\u7a0b\u6b63\u5e38\u9000\u51fa
                      \n}<\/p>\n

                      int status;
                      \nwaitpid(pid, &status, 0);<\/p>\n

                      if (WIFEXITED(status)) {
                      \n printf("\u6b63\u5e38\u9000\u51fa，\u9000\u51fa\u7801 = %d\\\\n", WEXITSTATUS(status)); \/\/ 42
                      \n}<\/p>\n

                      wait \u72b6\u6001\u5b8f\u5168\u5bb6\u6876：<\/span><\/p>\n\n\u5b8f<\/span>\u4f5c\u7528<\/span><\/tr>\n\n\n\n\n\n\n\n\n\n
                      WIFEXITED(status)<\/span><\/td>\n\u662f\u5426\u6b63\u5e38\u9000\u51fa（exit\/return）<\/span><\/td>\n<\/tr>\n
                      WEXITSTATUS(status)<\/span><\/td>\n\u6b63\u5e38\u9000\u51fa\u65f6\u7684\u9000\u51fa\u7801（\u4ec5 WIFEXITED \u4e3a\u771f\u65f6\u7528）<\/span><\/td>\n<\/tr>\n
                      WIFSIGNALED(status)<\/span><\/td>\n\u662f\u5426\u88ab\u4fe1\u53f7\u6740\u6b7b<\/span><\/td>\n<\/tr>\n
                      WTERMSIG(status)<\/span><\/td>\n\u6740\u6b7b\u5b83\u7684\u4fe1\u53f7\u7f16\u53f7（\u4ec5 WIFSIGNALED \u4e3a\u771f\u65f6\u7528）<\/span><\/td>\n<\/tr>\n
                      WCOREDUMP(status)<\/span><\/td>\n\u662f\u5426\u4ea7\u751f\u6838\u5fc3\u8f6c\u50a8（\u975e POSIX \u6807\u51c6，\u90e8\u5206\u7cfb\u7edf\u6709）<\/span><\/td>\n<\/tr>\n
                      WIFSTOPPED(status)<\/span><\/td>\n\u662f\u5426\u56e0\u4fe1\u53f7\u6682\u505c（\u914d\u5408 WUNTRACED）<\/span><\/td>\n<\/tr>\n
                      WSTOPSIG(status)<\/span><\/td>\n\u4f7f\u5176\u6682\u505c\u7684\u4fe1\u53f7\u7f16\u53f7<\/span><\/td>\n<\/tr>\n
                      WIFCONTINUED(status)<\/span><\/td>\n\u662f\u5426\u88ab SIGCONT \u6062\u590d（\u914d\u5408 WCONTINUED）<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                      \u5b8c\u6574\u5224\u65ad\u6a21\u677f：<\/span><\/p>\n

                      if (WIFEXITED(status)) {
                      \n printf("\u6b63\u5e38\u9000\u51fa，\u7801 %d\\\\n", WEXITSTATUS(status));
                      \n} else if (WIFSIGNALED(status)) {
                      \n printf("\u88ab\u4fe1\u53f7 %d \u6740\u6b7b\\\\n", WTERMSIG(status));
                      \n} else if (WIFSTOPPED(status)) {
                      \n printf("\u88ab\u4fe1\u53f7 %d \u6682\u505c\\\\n", WSTOPSIG(status));
                      \n}<\/p>\n

                      \u6838\u5fc3\u70b9：<\/span><\/p>\n

                      \u00a0 \u00a0status \u662f\u6253\u5305\u7684\u4f4d\u5b57\u6bb5，\u4e0d\u80fd\u76f4\u63a5\u6bd4\u8f83，\u5fc5\u987b\u7528\u5b8f\u89e3\u5305\u3002<\/span><\/p>\n

                      \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u5224\u65ad "\u662f\u5426\u6b63\u5e38\u9000\u51fa" \u770b WIFEXITED，\u53d6\u9000\u51fa\u7801\u770b WEXITSTATUS，\u4e24\u8005\u901a\u5e38\u6210\u5bf9\u51fa\u73b0\u3002<\/span><\/p>\n<\/p>\n

                      \n

                      \"\"<\/p>\n","protected":false},"excerpt":{"rendered":"

                      \/* MD \/ \u5bcc\u6587\u672c\u4e2d\u7684 .toc\uff08\u542b\u535a\u5ba2\u56ed\u642c\u5bb6\u7b49\u5d4c\u5957\u7ed3\u6784\uff09\uff1b.toc-box \u5728\u4fa7\u680f\uff0c\u4e0d\u53d7\u5f71\u54cd *\/#content_views .toc,\/* \u7f16\u8f91\u5668\u5e38\u5728\u76ee\u5f55\u524d\u540e\u63d2\u5165\u7a7a p\uff08:empty \u4ecd\u5360 20px\uff09\uff0c\u4e00\u5e76\u53bb\u6389\u907f\u514d\u9876\u7a7a\u9699 *\/#content_views.markdown_views > p:empty:has(+ .toc),#content_views.markdown_views > .toc + p:empty,\/* \u5bcc\u6587\u672c\u65e7\u7248\u76ee\u5f55\u6807\u8bb0 *\/#content<\/p>\n","protected":false},"author":2,"featured_media":116356,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[11820,58,190,43,44],"topic":[],"class_list":["post-116359","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-atomgit","tag-linux","tag-190","tag-43","tag-44"],"yoast_head":"\n\u3010Linux\u3011 \u81ea\u4e3bshell\u7f16\u5199\u5de9\u56fa\u590d\u4e60\u7bc7 - 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\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.wsisp.com\/helps\/116359.html","og_locale":"zh_CN","og_type":"article","og_title":"\u3010Linux\u3011 \u81ea\u4e3bshell\u7f16\u5199\u5de9\u56fa\u590d\u4e60\u7bc7 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"\/* MD \/ \u5bcc\u6587\u672c\u4e2d\u7684 .toc\uff08\u542b\u535a\u5ba2\u56ed\u642c\u5bb6\u7b49\u5d4c\u5957\u7ed3\u6784\uff09\uff1b.toc-box \u5728\u4fa7\u680f\uff0c\u4e0d\u53d7\u5f71\u54cd *\/#content_views .toc,\/* \u7f16\u8f91\u5668\u5e38\u5728\u76ee\u5f55\u524d\u540e\u63d2\u5165\u7a7a p\uff08:empty \u4ecd\u5360 20px\uff09\uff0c\u4e00\u5e76\u53bb\u6389\u907f\u514d\u9876\u7a7a\u9699 *\/#content_views.markdown_views > p:empty:has(+ .toc),#content_views.markdown_views > .toc + p:empty,\/* \u5bcc\u6587\u672c\u65e7\u7248\u76ee\u5f55\u6807\u8bb0 *\/#content","og_url":"https:\/\/www.wsisp.com\/helps\/116359.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-10-21T00:17:27+00:00","og_image":[{"url":"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/10\/20261021001722-6ad804927d5a1.png"}],"author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"12 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/116359.html","url":"https:\/\/www.wsisp.com\/helps\/116359.html","name":"\u3010Linux\u3011 \u81ea\u4e3bshell\u7f16\u5199\u5de9\u56fa\u590d\u4e60\u7bc7 - 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