FSTAT(1) BSD General Commands Manual FSTAT(1)
fstat -- display status of open files
fstat [-fnv] [-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.
-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''. Please see the BUGS section for issues with this option.
-M Extract values associated with the name list from the specified core instead of the default /dev/kmem.
-N 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 form.
-p Report all files open by the specified process.
-u 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 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 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.
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 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 speci-
fied, 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'' indicates
open for writing. This field is useful when trying to find the processes that are preventing a file system from being downgraded 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 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, 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 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. 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 con-
nected, 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 descriptor 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 system.
September 5, 2011 BSD