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

     -M core
             Extract values associated with the name list from the specified
             core instead of the running kernel.

     -N system
             Extract the name list from the specified system instead of the
             running kernel.

     -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

     -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 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.

     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    - 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),
     tcpdrop(8), vmstat(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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