1、安装命令工具
sudo apt-get -y install tree
2、可以查看关于tree命令的帮助信息
$ tree --help
usage: tree [-adfghilnpqrstuvxACDFNS] [-H baseHREF] [-T title ] [-L level [-R]]
[-P pattern] [-I pattern] [-o filename] [--version] [--help] [--inodes]
[--device] [--noreport] [--nolinks] [--dirsfirst] [--charset charset]
[--filelimit #] [<directory list>]
-a All files are listed.
-d List directories only.
-l Follow symbolic links like directories.
-f Print the full path prefix for each file.
-i Don't print indentation lines.
-q Print non-printable characters as '?'.
-N Print non-printable characters as is.
-p Print the protections for each file.
-u Displays file owner or UID number.
-g Displays file group owner or GID number.
-s Print the size in bytes of each file.
-h Print the size in a more human readable way.
-D Print the date of last modification.
-F Appends '/', '=', '*', or '|' as per ls -F.
-v Sort files alphanumerically by version.
-r Sort files in reverse alphanumeric order.
-t Sort files by last modification time.
-x Stay on current filesystem only.
-L level Descend only level directories deep.
3、使用方法（常用）
(1) 显示当前目录的树形结构
jianbao@jianbao-pc:/www/软件开发$ tree
.
├── PPT
│ └── PHP性能监控与优化.pptx
├── 电子书
│ ├── Linux.环境C程序设计.徐诚.扫描版.pdf
│ └── UNIX环境高级编程（中文第三版）_扫描版.pdf
├── 视频
│ └── PHP_C扩展
│ ├── PHP扩展开发教程.mp4
│ ├── swoole第三节第4部分.mp4
│ ├── swoole视频教程第3节 swoole服务器的进程_线程模型.mp4
│ └── 其他
│ ├── swoole-chat第二节第二部分.mp4
│ ├── swoole-chat第二节第三部分.mp4
└── 手册
└── php_enhanced_zh.chm
(2) 只查看当前第一级的目录和文件
$ tree -L 1
(3) 只查看当前第二级的目录和文件
$ tree -L 2
(4) 只查看当前第N级的目录和文件
$ tree -L N
(5) 把目录结构信息保存到文本中
$ tree -L 2 > /home/php-note.com/tree.txt