NAME
    fuser - identify processes using files or sockets

SYNOPSIS
    fuser [-a|-s] [-4|-6] [-n space] [-signal] [-kimuv] name ...
    fuser -l
    fuser -V

DESCRIPTION
    fuser displays the PIDs of processes using the specified files or file
    systems.  In the default display mode, each file name is followed by a
    letter denoting the type of access:

    c    current directory.

    e    executable being run.

    f    open file. f is omitted in default display mode.

    r    root directory.

    m    mmap'ed file or shared library.

    fuser returns a non-zero return code if none of the specified files is
    accessed or in case of a fatal error. If at least one access has been
    found, fuser returns zero.

    In order to look up processes using TCP and UDP sockets, the corre-
    sponding name space has to be selected with the -n option. By default
    fuser will look in both IPv6 and IPv4 sockets. To change the default,
    behavour, use the -4 and -6 options. The socket(s) can be specified by
    the local and remote port, and the remote address. All fields are
    optional, but commas in front of missing fields must be present:

    [lcl_port][,[rmt_host][,[rmt_port]]]

    Either symbolic or numeric values can be used for IP addresses and port
    numbers.

OPTIONS
    -a   Show all  files specified on the command line. By default, only
    files that are accessed by at least one process are shown.

    -k   Kill processes accessing the file. Unless changed with -signal,
    SIGKILL is sent. An fuser process never kills itself, but may
    kill other fuser processes. The effective user ID of the process
    executing  fuser is set to its real user ID before attempting to
    kill.

    -i   Ask the user for confirmation before killing a process. This
    option is silently ignored if -k is not present too.

    -l   List all known signal names.

    -m   name specifies a file on a mounted file system or a block device
    that is mounted. All processes accessing files on that file sys-
    tem are listed.  If a directory file is specified, it is auto-
    matically changed to name/. to use any file system that might be
    mounted on that directory.

    -n space
    Select a different name space. The name spaces file (file names,
    the default), udp (local UDP ports), and tcp (local TCP ports)
    are supported. For ports, either the port number or the sym-
    bolic name can be specified. If there is no ambiguity, the
    shortcut notation name/space (e.g. name/proto) can be used.

    -s   Silent operation. -u and -v are ignored in this mode. -a must
    not be used with -s.

    -signal
    Use the specified signal instead of SIGKILL when  killing pro-
    cesses. Signals can be specified either by name (e.g. -HUP) or
    by number (e.g. -1).

    -u   Append the user name of the process owner to each PID.

    -v   Verbose mode. Processes are shown in a ps-like style. The fields
    PID, USER and COMMAND are similar to ps. ACCESS shows how the
    process accesses the file. If the access is by the kernel  (e.g.
    in the case of  a mount point, a swap file, etc.), kernel is
    shown instead of the PID.

    -V   Display version information.

    -4   Search only for IPv4 sockets. This option must not be used with
    the -6 option and only has an effect with the tcp and udp names-
    paces.

    -6   Search only for IPv6 sockets. This option must not be used with
    the -4 option and only has an effect with the tcp and udp names-
    paces.

    -   Reset all options and set the signal back to SIGKILL.

FILES
    /proc  location of the proc file system

EXAMPLES
    fuser -km /home kills all processes accessing the file system /home in
    any way.

    if fuser -s /dev/ttyS1; then :; else something; fi invokes something if
    no other process is using /dev/ttyS1.

    fuser telnet/tcp shows all processes at the (local) TELNET port.

RESTRICTIONS
    Processes accessing the same file or file system several times in the
    same way are only shown once.

    If the same object is specified several times on the command line, some
    of those entries may be ignored.

    fuser may only be able to gather partial information unless run with
    privileges. As a consequence, files opened by processes belonging to
    other users may not be listed and executables may be classified as
    mapped only.

    Installing fuser SUID root will avoid problems associated with partial
    information, but may be undesirable for security and privacy reasons.

    udp and tcp name spaces, and UNIX domain sockets can't be searched with
    kernels older than 1.3.78.

    udp and tcp currently work with IPv6 and IPv4, but the address fields
    can only be IPv4 addresses.

    Accesses by the kernel are only shown with the -v option.

    The -k option only works on processes. If the user is the kernel, fuser
    will print an advice, but take no action beyond that.

AUTHOR
    Werner Almesberger <Werner.Almesberger@epfl.ch>

SEE ALSO
   kill(1),killall(1), lsof(8),ps(1), kill(2)