Two useful terminal commands for checking disk usage in Linux, are the commands df and du.
The first command, df, provides a table of file systems with information on free and used disk space. Note: Using the -h option provides the table in a human readable format.
The second command, du, can also retrieve disk usage information. Typing du into any directory will provide a list of files and directories at the specified location with their corresponding disk usage. However du may be more useful with the options -s and -h providing a human readable summary of the specified location on disk.
eg. display disk usage for the current working directory
or at a specified directory
du -hs directoryname