fuser(1)



FUSER(1)                         User Commands                        FUSER(1)

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 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,
       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 comparisions  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  file  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 seatbelt 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 SPACE, --namespace 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
              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  pro-
              cesses.    Signals   can  be  specified  either  by  name  (e.g.
              -HUP)orby 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 names-
              paces.

       -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 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.

       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 prob-
       lem 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.

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), pkill(1), ps(1), kill(2).

psmisc                            2016-04-04                          FUSER(1)

Man(1) output converted with man2html
list of all man pages