fuser [-a|-s|-c] [-4|-6] [-n space ] [-k [-i] [-signal ] ] [-muvf] name ...
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.