FSTAT(1) General Commands Manual FSTAT(1)
fstat - display status of open files
fstat [-fnosv] [-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 executable text, or kernel trace file for that process. If no
options are specified, fstat reports on all open files in the system.
The options are as follows:
-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 /usr/src resides, type
# fstat -f /usr/src
Extract values associated with the name list from the specified
core instead of the running kernel.
Extract the name list from the specified system instead of the
-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. Also, print the mode
of the file in octal instead of symbolic form.
-o Output file offset. Follow the size field with the descriptor's
offset. Useful for checking progress as a process works through
a large file. This information is only visible to the user or
-p pid Report all files open by the specified process.
-s Report per file io statistics in two additional columns `XFERS'
and `KBYTES'. This information is only visible to the user or
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 ignoring
them. Most of these data structures are dynamically created 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 running.
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 - executable 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, 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 under
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. It will be followed by an asterisk
(`*') if the inode is unlinked from disk.
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.
R/W This column describes the properties of the file descriptor:
r Open for reading
w Open for writing
e close-on-exec flag is set
This field is useful when trying to find the processes that are
preventing a file system from being downgraded to read-only.
SZ | DV
If the file is not a character or block special file, prints the
size of the file in bytes. 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.
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
XFERS Displays number of total data transfers performed on the file.
Displays total number of Kbytes written and read to the file.
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, it's the address of the
socket pcb and the address of the connected pcb (if connected).
Otherwise the protocol number and address of the socket itself are
printed. The attempt is to make enough information available to permit
further analysis 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. These
addresses are only visible to the superuser, otherwise 0x0 is printed.
Sockets that have been disassociated from a protocol control block will
always print 0x0. A unidirectional UNIX-domain socket indicates the
direction of flow with an arrow ("<-" or "->"), and a full duplex socket
shows a double arrow ("<->").
For AF_INET and AF_INET6 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.
A `*' is used to indicate an INADDR_ANY binding. In this case, the use
of the arrow ("<--" or "-->") indicates the direction the socket
connection was created.
If the socket has been spliced to or from another socket (see
setsockopt(2) and SO_SPLICE) then fstat prints a thick arrow ("<==>",
"<==", or "==>"), followed by the address and endpoint information of the
other socket in the splice, if available.
Every pipe is printed as an address which is the same for both sides of
the pipe and a state that is built of the letters "RWE". W - The pipe
blocks waiting for the reader to read data. R - The pipe blocks waiting
for the writer to write data. E - The pipe is in EOF state.
Each kqueue(2) is printed with some information as to queue length.
Since these things are normally serviced quickly, it is likely that
nothing of real importance can be discerned.
netstat(1), nfsstat(1), ps(1), systat(1), top(1), iostat(8), pstat(8),
The fstat command appeared in 4.3BSD-Tahoe.
Sockets in use by the kernel, such as those opened by nfsd(8), will not
be seen by fstat, even though they appear in netstat(1).
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
descriptor changes, fstat does not attempt to translate the internet
address and port numbers into symbolic names.
OpenBSD 6.4 March 16, 2018 OpenBSD 6.4
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