# To display a recursive directory tree#显示递归目录树
tree
# To make tree output contents from path `/foo/bar`#从路径`/ foo / bar`制作树输出内容
tree /foo/bar
# To make tree omit any empty directories from the output#使树从输出中省略任何空目录
tree --prune# To list directories only (`-d`), and at a max depth of two levels (`-L`)#仅列出目录(`-d`),并且最大深度为两级(`-L`)
tree -d-L2