NAME
  df - report free disk space

SYNOPSIS
  df [-h] [-k] [-P] [-t] [file]

DESCRIPTION
  The df utility shall write the amount of available space and file slots for
  file systems on which the invoking user has appropriate read access. File
  systems shall be specified by the file operands; when none are specified,
  information shall be written for all file systems.The format of the default
  output from df is unspecified, but all space figures are reported in 512-byte
  units, unless the -k option is specified. This output shall contain at least
  the file system names, amount of available space on each of these file systems,
  and, if no options other than -t are specified, the number of free file slots,
  or inodes, available; when -t is specified, the output shall contain the total
  allocated space as well.

OPERANDS
  file  A pathname of a file within the hierarchy of the desired file system.
        If a file other than a FIFO, a regular file, a directory, or a special
        file representing the device containing the file system (for example,
        /dev/dsk/0s1) is specified, the results are unspecified. If the file
        operand names a file other than a special file containing a file
        system, df shall write the amount of free space in the file system
        containing the specified file operand. Otherwise, df shall write the
        amount of free space in that file system.

OPTIONS
  -h  Print sizes in powers of 1024 (e.g., 1023M)
  -k  Use 1024-byte units, instead of the default 512-byte units, when writing
      space figures.
  -P  Produce a POSIX output
  -t  Include total allocated-space figures in the output.