Display size of all subdirectories from current directory in Linux

To display the size the command is "du".

du

You could check the man page and help for the command, a useful modifier is "-h", which as in the "ls" command it converts the size to a more practical representation.

du -h

Show and display human readable size in files and directories listing on Linux

"h" is the ls modifier required to display GB, MB, KB and related information.

ls -lh
ls -lah