FUSER(1)                                                         User Commands                                                        FUSER(1)


       fuser - identify processes using files or sockets


       fuser [-fuv] [-a|-s] [-4|-6] [-c|-m|-n  space ] [-k [-i] [-M] [-w] [-SIGNAL ] ] name ...
       fuser -l
       fuser -V


       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


       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.


       -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

       -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.

       -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/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.

              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

       -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

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


       /proc     location of the proc file system


       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.


       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

       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.


       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

       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.


       Werner Almesberger <werner@almesberger.net>

       Craig Small <csmall@enc.com.au>


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

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