Disk Usage/Size
All files/folders with sizes; Total size at bottom
du -h </path/to/directory>
One line, shows top level folder size including sub-folders/files.
du -hs </path/to/directory>
Total folder/file size recursive for multiple folders
du -sch </path/to/directory> </path/to/directory> </path/to/directory>
Show directory tree structure from directory down with count
tree -sd </path/to/directory>
