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14.1 `df': Report file system disk space usage

`df' reports the amount of disk space used and available on file
systems.  Synopsis:

     df [OPTION]... [FILE]...

   With no arguments, `df' reports the space used and available on all
currently mounted file systems (of all types).  Otherwise, `df' reports
on the file system containing each argument FILE.

   Normally the disk space is printed in units of 1024 bytes, but this
can be overridden (*note Block size::).  Non-integer quantities are
rounded up to the next higher unit.

   If an argument FILE is a disk device file containing a mounted file
system, `df' shows the space available on that file system rather than
on the file system containing the device node (i.e., the root file
system).  GNU `df' does not attempt to determine the disk usage on
unmounted file systems, because on most kinds of systems doing so
requires extremely nonportable intimate knowledge of file system

   The program accepts the following options.  Also see *note Common

     Include in the listing dummy file systems, which are omitted by
     default.  Such file systems are typically special-purpose
     pseudo-file-systems, such as automounter entries.

     Scale sizes by SIZE before printing them (*note Block size::).
     For example, `-BG' prints sizes in units of 1,073,741,824 bytes.

     Do not resolve mount point and show statistics directly for a
     file. It can be especially useful for NFS mount points if there is
     a boundary between two storage policies behind the mount point.

     Print a grand total of all arguments after all arguments have been
     processed.  This can be used to find out the total disk size, usage
     and available space of all listed devices.

     Append a size letter to each size, such as `M' for mebibytes.
     Powers of 1024 are used, not 1000; `M' stands for 1,048,576 bytes.
     This option is equivalent to `--block-size=human-readable'.  Use
     the `--si' option if you prefer powers of 1000.

     Equivalent to `--si'.

     List inode usage information instead of block usage.  An inode
     (short for index node) contains information about a file such as
     its owner, permissions, timestamps, and location on the disk.

     Print sizes in 1024-byte blocks, overriding the default block size
     (*note Block size::).  This option is equivalent to

     Limit the listing to local file systems.  By default, remote file
     systems are also listed.

     Do not invoke the `sync' system call before getting any usage data.
     This may make `df' run significantly faster on systems with many
     disks, but on some systems (notably SunOS) the results may be
     slightly out of date.  This is the default.

     Use the POSIX output format.  This is like the default format
     except for the following:

       1. The information about each file system is always printed on
          exactly one line; a mount device is never put on a line by
          itself.  This means that if the mount device name is more
          than 20 characters long (e.g., for some network mounts), the
          columns are misaligned.

       2. The labels in the header output line are changed to conform
          to POSIX.

       3. The default block size and output format are unaffected by the
          `DF_BLOCK_SIZE', `BLOCK_SIZE' and `BLOCKSIZE' environment
          variables.  However, the default block size is still affected
          by `POSIXLY_CORRECT': it is 512 if `POSIXLY_CORRECT' is set,
          1024 otherwise.  *Note Block size::.

     Append an SI-style abbreviation to each size, such as `M' for
     megabytes.  Powers of 1000 are used, not 1024; `M' stands for
     1,000,000 bytes.  This option is equivalent to `--block-size=si'.
     Use the `-h' or `--human-readable' option if you prefer powers of

     Invoke the `sync' system call before getting any usage data.  On
     some systems (notably SunOS), doing this yields more up to date
     results, but in general this option makes `df' much slower,
     especially when there are many or very busy file systems.

     Limit the listing to file systems of type FSTYPE.  Multiple file
     system types can be specified by giving multiple `-t' options.  By
     default, nothing is omitted.

     Print each file system's type.  The types printed here are the
     same ones you can include or exclude with `-t' and `-x'.  The
     particular types printed are whatever is supported by the system.
     Here are some of the common names (this list is certainly not

          An NFS file system, i.e., one mounted over a network from
          another machine.  This is the one type name which seems to be
          used uniformly by all systems.

    `4.2, ufs, efs...'
          A file system on a locally-mounted hard disk.  (The system
          might even support more than one type here; Linux does.)

    `hsfs, cdfs'
          A file system on a CD-ROM drive.  HP-UX uses `cdfs', most
          other systems use `hsfs' (`hs' for "High Sierra").

          An MS-DOS file system, usually on a diskette.

     Limit the listing to file systems not of type FSTYPE.  Multiple
     file system types can be eliminated by giving multiple `-x'
     options.  By default, no file system types are omitted.

     Ignored; for compatibility with System V versions of `df'.

   An exit status of zero indicates success, and a nonzero value
indicates failure.  Failure includes the case where no output is
generated, so you can inspect the exit status of a command like `df -t
ext3 -t reiserfs DIR' to test whether DIR is on a file system of type
`ext3' or `reiserfs'.