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] [-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.

       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.

       -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.

       -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/Ispace (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 access  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.

       -      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 pro-
       cesses 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.

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.

       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

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

AUTHORS
       Werner Almesberger <wernerATalmesberger.net>

       Craig Small <csmallATenc.au>

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



Linux                                                      2009-11-23                                                   FUSER(1)