Linux directory tree
https://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
https://en.wikipedia.org/wiki/Unix_filesystem#Conventional_directory_layout
https://www.w3resource.com/linux-system-administration/linux-file-tree.php
https://en.wikipedia.org/wiki/Tree_(command)
https://en.wikipedia.org/wiki/File:Unix_history-simple.svg
https://upload.wikimedia.org/wikipedia/commons/7/77/Unix_history-simple.svg
D: 00-testinglight-ios-apph5_app>bash
xgqfrms@NB2-XIAGQ:/mnt/d/000-testing/light-ios-app/h5_app$ tree
.
├── app.js
├── app.less
├── css
│ ├── reset.css
│ └── style.less
├── images
│ ├── about-active.png
│ ├── about.png
│ ├── contact-active.png
│ ├── contact.png
│ ├── home-active.png
│ ├── home.png
│ ├── more.png
│ └── scan.png
├── index.html
├── lib
│ ├── package.json
│ └── px2rem.js
├── project.json
├── ui
│ └── ui.vue
└── view
├── index
│ ├── about.vue
│ ├── contact.vue
│ └── home.vue
└── index.vue
6 directories, 21 files
xgqfrms@NB2-XIAGQ:/mnt/d/000-testing/light-ios-app/h5_app$
tree level
$ tree -L 3 -I "node_modules|bower_components"
https://www.cnblogs.com/xgqfrms/p/10729411.html