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 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 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 nota-
              tion 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)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
       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 rea-
       sons.

       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)