NAME

       fuser - identify processes using files or sockets

SYNOPSIS

       fuser [-fuv] [-a|-s] [-4|-6] [-c|-m|-n space] [ -k [-i] [-M] [-w] [-SIGNAL] ] 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.
              F      open file for writing.  F is omitted in default display mode.
              r      root directory.
              m      mmap'ed file or shared library.
              .      Placeholder, omitted in default display mode.

       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 corresponding 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 behavior, 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.

       fuser outputs only the PIDs to stdout, everything else is sent to stderr.

OPTIONS

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

       -c     Same as -m option, used for POSIX compatibility.

       -f     Silently ignored, used for POSIX compatibility.

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

       -I, --inode
              For the name space file let all comparisons be based on the inodes of the specified
              file(s) and never on the file names even on network based file systems.

       -l, --list-signals
              List all known signal names.

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

       -M, --ismountpoint
              Request will be fulfilled  only  if  NAME  specifies  a  mountpoint.   This  is  an
              invaluable seat belt which prevents you from killing the machine if NAME happens to
              not be a filesystem.

       -w     Kill only processes which have write access.  This option is silently ignored if -k
              is not present too.

       -n NAMESPACE, --namespace NAMESPACE
              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 symbolic name can be specified.  If there is no ambiguity, the
              shortcut notation name/space (e.g., 80/tcp) can be used.

       -s, --silent
              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 processes.  Signals can be
              specified either by name (e.g., -HUP) or by number  (e.g.,  -1).   This  option  is
              silently ignored if the -k option is not used.

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

       -v, --verbose
              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.
              Verbose  mode  will  also  show when a particular file is being accessed as a mount
              point, knfs export or swap file.  In this case kernel is shown instead of the PID.

       -V, --version
              Display version information.

       -4, --ipv4
              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 namespaces.

       -6, --ipv6
              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 namespaces.

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 command; fi
              invokes command 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.

       fuser cannot report on any processes that it doesn't have permission to look at  the  file
       descriptor table for.  The most common time this problem occurs is when looking for TCP or
       UDP sockets when running fuser as a non-root user.  In this  case  fuser  will  report  no
       access.

       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.

       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.

       fuser will not see block devices mounted by processes  in  a  different  mount  namespace.
       This  is  due  to the device ID shown in the process' file descriptor table being from the
       process namespace, not fuser's; meaning it won't match.

BUGS

       fuser -m /dev/sgX will show (or kill with the -k flag) all processes, even  if  you  don't
       have that device configured.  There may be other devices it does this for too.

       The  mount -m option will match any file within the same device as the specified file, use
       the -M option as well if you mean to specify only the mount point.

SEE ALSO

       kill(1), killall(1), lsof(8), mount_namespaces(7), pkill(1), ps(1), kill(2).