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 1KB 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).
Include empty filesystems (those with 0 blocks).
Show space as n-byte blocks.
Print sizes in a format friendly to human readers (e.g., 1.9G instead of 1967156).
Like -h, but show as power of 1000 rather than 1024.
Report free, used, and percent-used inodes.
Print sizes in kilobytes.
Show local filesystems only.
Print sizes in megabytes.
Show results without invoking sync first (i.e., without flushing the buffers). This is the default.
Use POSIX output format (i.e., print information about each filesystem on exactly one line).
Invoke sync (flush buffers) before getting and showing sizes.
Show only type filesystems.
Print the type of each filesystem in addition to the sizes.
Show only filesystems that are not of type type.
Print help message and then exit.