MAN page from Old RedHat 5.X psmisc-17-3.i386.rpm

FUSER

Section: User Commands (1)
Updated: Feb 3, 1998
Index

NAME

fuser - identify processes using files or sockets

SYNOPSIS

fuser[-a|-s][-n space][-signal][-kmuv]name ...[-][-n space][-signal][-kmuv]name ...
fuser -l
fuser -V

DESCRIPTION

fuserdisplays the PIDs of processes using the specified files or file systems.In the default display mode, each file name is followed by a letter denotingthe 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 filesis accessed or in case of a fatal error. If at least one access has beenfound, fuser returns zero.

In order to look up processes using TCP and UDP sockets, the correspondingname space has to be selected with the -n option. Then the socket(s) canbe specified by the local and remote port, and the remote address. All fieldsare 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 portnumbers.

OPTIONS

-a: Show all files specified on the command line. By default, only files that areaccessed 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 killother fuser processes. The effective user ID of the process executingfuser is set to its real user ID before attempting to kill.
-l: List all known signal names.
-m: name specifies a file on a mounted file system or a block device thatis mounted. All processes accessing files on that file system are listed.If a directory file is specified, it is automatically changed toname/. to use any file system that might be mounted on thatdirectory.
-n space: Select a different name space. The name spaces file (file names, thedefault), udp (local UDP ports), and tcp (local TCP ports) aresupported. For ports, either the port number or the symbolic name can bespecified. If there is no ambiguity, the shortcut notationname/space (e.g. name/proto) can be used.
-s: Silent operation. -a, -u and -v are ignored in this mode.
-signal: Use the specified signal instead of SIGKILL when killing processes. Signalscan 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 processaccesses the file. If the access is by the kernel (e.g. in the case of amount point, a swap file, etc.), kernel is shown instead of the PID.
-V: Display version information.
-: 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 /homein any way.

if fuser -s /dev/ttyS1; then :; else something; fi invokessomething 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 wayare only shown once.

If the same object is specified several times on the command line, some ofthose entries may be ignored.

fuser may only be able to gather partial information unless run withprivileges. As a consequence, files opened by processes belonging to otherusers may not be listed and executables may be classified as mapped only.

Installing fuser SUID root will avoid problems associated withpartial information, but may be undesirable for security and privacyreasons.

udp and tcp name spaces, and UNIX domain sockets can't besearched with kernels older than 1.3.78.

udp and tcp currently only work for IPv4.

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

Werner Almesberger <werner.almesbergerAATTlrc.di.epfl.ch>

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