{
  "meta": {
    "version": "1.0",
    "title": "Linux 命令学习课程 - 沙盒练习题",
    "author": "Dev Agent",
    "created": "2026-03-04"
  },
  "levels": [
    {
      "id": "level_1_intro",
      "title": "入门篇：熟悉终端",
      "description": "前5个命令，让你快速上手 Linux 终端",
      "challenges": [
        {
          "id": "pwd_1",
          "title": "我在哪？",
          "description": "使用 `pwd` 命令查看你当前所在的目录",
          "hint": "直接输入 pwd 回车",
          "success_test": "if output == '/' then pass",
          "solution": ["pwd"],
          "fail_message": "❌ 还不对！试试 `pwd` 命令"
        },
        {
          "id": "ls_1",
          "title": "看看周围",
          "description": "使用 `ls` 命令列出 `/sandbox` 下的所有子目录和文件",
          "hint": "输入 ls /sandbox",
          "success_test": "if output contains 'users' and 'projects' and 'logs' then pass",
          "solution": ["ls /sandbox", "ls /"],
          "fail_message": "❌ 还差一点！试试 `ls /sandbox` 或 `ls /`"
        },
        {
          "id": "cd_1",
          "title": "进入用户区",
          "description": "使用 `cd` 命令进入 /users 目录",
          "hint": "先 cd 进去，再用 pwd 确认",
          "success_test": "if cwd == '/users' then pass",
          "solution": ["cd /users", "cd /"],
          "fail_message": "❌ 还没到 /users！试试 `cd /users`"
        },
        {
          "id": "cat_1",
          "title": "读取文件",
          "description": "使用 `cat` 命令读取 /users/alice.txt 的内容",
          "hint": "cat /users/alice.txt",
          "success_test": "if output contains 'Alice' and 'Linux' then pass",
          "solution": ["cat /users/alice.txt"],
          "fail_message": "❌ 记得完整路径！试试 `cat /users/alice.txt`"
        },
        {
          "id": "echo_1",
          "title": "打招呼",
          "description": "使用 `echo` 打印一句话：Hello Linux!",
          "hint": "echo 黑客996",
          "success_test": "if output contains 'Hello Linux' then pass",
          "solution": ["echo Hello Linux!", "echo 'Hello Linux!'"],
          "fail_message": "❌ 别忘了空格！试试 `echo Hello Linux!`"
        }
      ]
    },
    {
      "id": "level_2_files",
      "title": "文件操作",
      "description": "创建、复制、移动、查看文件内容（只读沙盒）",
      "challenges": [
        {
          "id": "tail_1",
          "title": "看文件末尾",
          "description": "使用 `tail -n 3` 查看 /projects/backend/app.py 的最后 3 行",
          "hint": "tail -n 3 /projects/backend/app.py",
          "success_test": "if output contains 'main' then pass",
          "solution": ["tail -n 3 /projects/backend/app.py"],
          "fail_message": "❌ 记得 `-n` 参数！试试 `tail -n 3`"
        },
        {
          "id": "head_1",
          "title": "看文件开头",
          "description": "使用 `head -n 2` 查看 /logs/access.log 的前 2 行",
          "hint": "head -n 2 /logs/access.log",
          "success_test": "if output contains '2024-01-01' then pass",
          "solution": ["head -n 2 /logs/access.log"],
          "fail_message": "❌ 别忘了 `-n 2`！试试 `head -n 2`"
        },
        {
          "id": "mkdir_1",
          "title": "创建目录",
          "description": "使用 `mkdir` 在 /projects 下创建一个叫 mycode 的目录",
          "hint": "mkdir /projects/mycode",
          "success_test": "if output contains 'mycode' then pass",
          "solution": ["mkdir /projects/mycode"],
          "fail_message": "❌ 路径别写错！试试 `mkdir /projects/mycode`"
        }
      ]
    },
    {
      "id": "level_3_search",
      "title": "搜索高手",
      "description": "grep/fun/wc/sort 组合技",
      "challenges": [
        {
          "id": "grep_1",
          "title": "查找关键词",
          "description": "使用 `grep` 在 /users/alice.txt 中查找包含 'Linux' 的行",
          "hint": "grep Linux /users/alice.txt",
          "success_test": "if output contains 'Linux' then pass",
          "solution": ["grep Linux /users/alice.txt"],
          "fail_message": "❌ 格式是 `grep pattern file`！试试 `grep Linux`"
        },
        {
          "id": "wc_1",
          "title": "统计行数",
          "description": "统计 /projects/backend/app.py 的总行数",
          "hint": "wc -l /projects/backend/app.py",
          "success_test": "if output contains '4' then pass",
          "solution": ["wc -l /projects/backend/app.py"],
          "fail_message": "❌ `-l` 是行数参数！试试 `wc -l`"
        }
      ]
    }
  ]
}