linux下我们经常要查看目录的组织结构，tree命令以树形结构显示文件目录。
直接使用tree dir显示目录下所有文件和文件夹：
$ tree go go ├── build.sh ├── compile-run.sh ├── main └── main.go
tree -d选项只查看目录下文件夹：
$ tree -d cmake cmake ├── cmake_exe │ └── CMakeFiles │ ├── 3.5.1 │ │ ├── CompilerIdC │ │ └── CompilerIdCXX │ ├── CMakeTmp │ └── main.dir ├── cmake_lib │ ├── bin │ ├── CMakeFiles │ │ ├── 3.5.1 │ │ │ ├── CompilerIdC │ │ │ └── CompilerIdCXX │ │ └── CMakeTmp │ ├── lib │ │ └── CMakeFiles │ │ └── libhello.dir │ └── src │ └── CMakeFiles │ └── hello.dir └── cmake_so
tree -L leve查看目录树深度：
$ tree -d -L 2 shell
shell
├── autoupdate
│ └── tools
└── expect-dir
├── bin
├── expect5.45
├── expect-tool
└── tcl8.4.11
7 directories
在shell终端输入tree --help查看所有选项：
$ tree --help usage: tree [-acdfghilnpqrstuvxACDFJQNSUX] [-H baseHREF] [-T title ] [-L level [-R]] [-P pattern] [-I pattern] [-o filename] [--version] [--help] [--inodes] [--device] [--noreport] [--nolinks] [--dirsfirst] [--charset charset] [--filelimit[=]#] [--si] [--timefmt[=]<f>] [--sort[=]<name>] [--matchdirs] [--ignore-case] [--] [<directory list>] ------- Listing options ------- -a All files are listed. -d List directories only. -l Follow symbolic links like directories. -f Print the full path prefix for each file. -x Stay on current filesystem only. -L level Descend only level directories deep. -R Rerun tree when max dir level reached. -P pattern List only those files that match the pattern given. -I pattern Do not list files that match the given pattern. --ignore-case Ignore case when pattern matching. --matchdirs Include directory names in -P pattern matching. --noreport Turn off file/directory count at end of tree listing. --charset X Use charset X for terminal/HTML and indentation line output. --filelimit # Do not descend dirs with more than # files in them. --timefmt <f> Print and format time according to the format <f>. -o filename Output to file instead of stdout. -------- File options --------- -q Print non-printable characters as '?'. -N Print non-printable characters as is. -Q Quote filenames with double quotes. -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. --si Like -h, but use in SI units (powers of 1000). -D Print the date of last modification or (-c) status change. -F Appends '/', '=', '*', '@', '|' or '>' as per ls -F. --inodes Print inode number of each file. --device Print device ID number to which each file belongs. ------- Sorting options ------- -v Sort files alphanumerically by version. -t Sort files by last modification time. -c Sort files by last status change time. -U Leave files unsorted. -r Reverse the order of the sort. --dirsfirst List directories before files (-U disables). --sort X Select sort: name,version,size,mtime,ctime. ------- Graphics options ------ -i Don't print indentation lines. -A Print ANSI lines graphic indentation lines. -S Print with CP437 (console) graphics indentation lines. -n Turn colorization off always (-C overrides). -C Turn colorization on always. ------- XML/HTML/JSON options ------- -X Prints out an XML representation of the tree. -J Prints out an JSON representation of the tree. -H baseHREF Prints out HTML format with baseHREF as top directory. -T string Replace the default HTML title and H1 header with string. --nolinks Turn off hyperlinks in HTML output. ---- Miscellaneous options ---- --version Print version and exit. --help Print usage and this help message and exit. -- Options processing terminator.