LINUX COMMANDS

fdisk [options] [device]

du [options] [directories]

Print disk usage (as the number of 1 KB blocks used by each named directory and its subdirectories; default is the current directory).

Options
-0, --null
End output lines with null, not newline.
-a, --all
Print disk usage for all files, not just subdirectories.
--apparent-size
Print the apparent sizes, not disk usage.

df [options] [name]

Report the amount of free disk space available on all mounted filesystems or on the given name. (df cannot report on unmounted
filesystems.) Disk space is shown in 1 KB blocks (default) or 512- byte blocks if the environment variable POSIXLY_CORRECT is set.
name can be a device name (e.g., /dev/hd*), the directory name of a mounting point (e.g., /usr), or a directory name (in which case df reports on the entire filesystem in which that directory is mounted).