list directory contents in a tree structure
testDirectory
├──level1
│ ├──level11
│ │ ├──a.js
│ │ └──e.js
│ └──level12
│ ├──b.js
│ └──f.js
└──level2
├──c.js
└──d.js
npm install -g lstree
lstree -h
ls
ls -o <outfile-path>
ls -d <directory-path> -o <outfile-path>
when directory is too big, the process will down