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FSTAT(1) NetBSD General Commands Manual FSTAT(1)
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fstat -- display status of open files
fstat [-AfnOv] [-M core] [-N system] [-p pid] [-u user] [file ...]
fstat identifies open files. A file is considered open by a process if
it was explicitly opened, is the working directory, root directory,
active pure text, or kernel trace file for that process. If no options
are specified, fstat reports on all open files in the system.
-A Add an output column with the address of the kernel object
(vnode or file), that can be matched with pstat(8) output.
-f Restrict examination to files open in the same file systems
as the named file arguments, or to the file system containing
the current directory if there are no additional filename
arguments. For example, to find all files open in the file
system where the directory /var/log resides, type ``fstat -f
/var/log''. Please see the BUGS section for issues with this
-M core Extract values associated with the name list from the speci-
fied core instead of the default /dev/kmem.
-N system Extract the name list from the specified system instead of
the default /netbsd.
-n Numerical format. Print the device number (maj,min) of the
file system the file resides in rather than the mount point
name; for special files, print the device number that the
special device refers to rather than the filename in /dev;
and print the mode of the file in octal instead of symbolic
-O Report file offsets instead of sizes.
-p process Report all files open by the specified process.
-u user Report all files open by the specified user.
-v Verbose mode. Print error messages upon failures to locate
particular system data structures rather than silently ignor-
ing them. Most of these data structures are dynamically cre-
ated or deleted and it is possible for them to disappear
while fstat is running. This is normal and unavoidable since
the rest of the system is running while fstat itself is run-
file ... Restrict reports to the specified files.
The following fields are printed:
USER The username of the owner of the process (effective UID).
CMD The command name of the process.
PID The process ID.
FD The file number in the per-process open file table or one of the
following special names:
text pure text inode
wd current working directory
root root inode
tr kernel trace file
If the file number is followed by an asterisk (``*''), the file is
not an inode, but rather a socket, FIFO, or there is an error. In
this case the remainder of the line doesn't correspond to the
remaining headers -- the format of the line is described later
MOUNT If the -n flag wasn't specified, this header is present and is the
pathname that the file system the file resides in is mounted on.
DEV If the -n flag is specified, this header is present and is the
major/minor number of the device that this file resides in.
INUM The inode number of the file.
MODE The mode of the file. If the -n flag isn't specified, the mode is
printed using a symbolic format (see strmode(3)); otherwise, the
mode is printed as an octal number.
SZ|DV or OFFS
If the file is not a character or block special file, prints the
size of the file in bytes (or the offset if the -O is specified).
Otherwise, if the -n flag is not specified, prints the name of the
special file as located in /dev. If that cannot be located, or
the -n flag is specified, prints the major/minor device number
that the special device refers to.
R/W This column describes the access mode that the file allows. The
letter ``r'' indicates open for reading; the letter ``w'' indi-
cates open for writing. This field is useful when trying to find
the processes that are preventing a file system from being down-
graded to read-only.
NAME If filename arguments are specified and the -f flag is not, then
this field is present and is the name associated with the given
file. Normally the name cannot be determined since there is no
mapping from an open file back to the directory entry that was
used to open that file. Also, since different directory entries
may reference the same file (via ln(1)), the name printed may not
be the actual name that the process originally used to open that
The formatting of open sockets depends on the protocol domain. In all
cases the first field is the domain name and the second field is the
socket type (stream, dgram, etc.). The remaining fields are protocol
dependent. For TCP, it is the address of the tcpcb, and for UDP, the
inpcb (socket pcb). For UNIX domain sockets, its the address of the
socket pcb and the name of the file if available. Otherwise the address
of the connected pcb is printed (if connected). For other domains, the
protocol number and address of the socket itself are printed. The
attempt is to make enough information available to permit further analy-
sis without duplicating netstat(1).
For example, the addresses mentioned above are the addresses which the
``netstat -A'' command would print for TCP, UDP, and UNIX domain. For
kernels compiled with PIPE_SOCKETPAIR pipes appear as connected UNIX
domain stream sockets. A unidirectional UNIX domain socket indicates the
direction of flow with an arrow (``<-'' or ``->''), and a full duplex
socket shows a double arrow (``<->'').
For internet sockets fstat also attempts to print the internet address
and port for the local end of a connection. If the socket is connected,
it also prints the remote internet address and port. An asterisk (``*'')
is used to indicate an INADDR_ANY binding.
netstat(1), nfsstat(1), ps(1), sockstat(1), systat(1), vmstat(1),
fstat(2), iostat(8), pstat(8)
The fstat command appeared in 4.3BSD-Tahoe.
Since fstat takes a snapshot of the system, it is only correct for a very
short period of time.
Moreover, because DNS resolution and YP lookups cause many file descrip-
tor changes, fstat does not attempt to translate the internet address and
port numbers into symbolic names.
Note that the -f option will not list UNIX domain sockets open in the
file system, because the pathnames in the sockets may not be absolute and
are not deterministic. To find all the UNIX domain sockets, use fstat to
list all the sockets, and look for the ones that maybe belong in the file
NetBSD 10.99 September 6, 2019 NetBSD 10.99