With these three simple commands—mv, cp, and mkdir—you’ll be able to copy and move files, as well as create directories to hold files anywhere in your Mac’s file system.

Once you've done so, and either restarted the terminal, or just pasted the same code into your active terminal, you can create folders, or even folder hierarchies with a single step, like so: mkcd ...

In Terminal, you use the command mkdir to create new directories (folders). For instance, mkdir “My Folder” will create a folder named My Folder in the current directory.