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NAME    [Toc]    [Back]

       fuser - identify processes using files or sockets

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

       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 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,
       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:


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

OPTIONS    [Toc]    [Back]

       -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

       -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 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.

       -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 symbolic
 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.

	      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).

       -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 namespaces.

       -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 namespaces.

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

FILES    [Toc]    [Back]

       /proc	 location of the proc file system

EXAMPLES    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       Werner Almesberger <Werner.Almesberger@epfl.ch>

SEE ALSO    [Toc]    [Back]

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

Linux			       October 25, 1999 		      FUSER(1)
[ Back ]
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