fuser
identify processes using files or sockets
see also :
kill - killall - lsof - pkill - ps
Synopsis
fuser
[-fuv] [-a|-s]
[-4|-6]
[-c|-m|-n
space] [ -k [-i]
[-M] [-w]
[-SIGNAL] ] name ...
fuser -l
fuser -V
add an example, a script, a trick and tips
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.
source
echo "kill
zhtserver"
fuser -k 50001/tcp
fuser -k 50002/tcp
fuser -k 50003/tcp
fuser -k 50004/tcp
fuser -k 50004/tcp
fuser -k 50005/tcp
fuser -k 50006/tcp
fuser -k 50007/tcp
fuser -k 50008/tcp
killall -9 peerserver
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.
-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/space (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)orby
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
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.
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.
see also
kill ,
killall , lsof , pkill ,
ps , kill.