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FUSER(1)			 User Commands			      FUSER(1)



NAME
       fuser - identify processes using files or sockets

SYNOPSIS
       fuser [-a|-s|-c] [-4|-6] [-n  space ] [-k [-i] [-signal ] ] [-muvf]
       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 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     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  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     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 sys-
	      tem are listed.  If a directory file is specified, it  is	 auto-
	      matically 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/Ispace (e.g. 80/tcp ) can be used.

       -s     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)  or
	      by  number  (e.g. -1). This option is silently ignored if the -k
	      option is not used.

       -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 names-
	      paces.

       -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 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.

       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 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

AUTHORS
       Werner Almesberger <werner@almesberger.net>

       Craig Small <csmall@small.dropbear.id.au>

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



Linux				  2005-11-05			      FUSER(1)
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