FSTAT(1) FreeBSD General Commands Manual FSTAT(1)
NAME
fstat - identify active files
SYNOPSIS
fstat [-fmnsv] [-M core] [-N system] [-p pid] [-u user] [file ...]
DESCRIPTION
The fstat utility identifies open files. A file is considered open by a
process if it was explicitly opened, is the working directory, root
directory, jail 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 for processes the user has access to.
The following options are available:
-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 default /dev/kmem.
-m Include memory-mapped files in the listing; normally these are
excluded due to the extra processing required.
-N system Extract the name list from the specified system instead of the
default, which is the kernel image the system has booted from.
-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 pid Report all files open by the specified process.
-s Print socket endpoint information.
-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:
jail jail root directory
mmap memory-mapped file
root root inode
text executable text inode
tr kernel trace file
wd current working directory
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 does not correspond to the
remaining headers-- the format of the line is described later
under SOCKETS.
MOUNT If the -n flag was not 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
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 is not 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 a semaphore, prints the current value of the
semaphore. If the file is not a character or block special,
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.
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 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
file.
SOCKETS
The formatting of open sockets depends on the protocol domain. In all
cases the first field is the domain name, the second field is the socket
type (stream, dgram, etc.), and the third is the socket flags field (in
hex). 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 address of the
connected pcb (if connected). Otherwise the protocol number and address
of the socket itself are printed.
For example, the addresses mentioned above are the addresses which the
`netstat -A' command would print for TCP, UDP, and UNIX-domain. Note
that since pipes are implemented using sockets, a pipe appears as a
connected UNIX-domain stream socket. A unidirectional UNIX-domain socket
indicates the direction of flow with an arrow (`<-' or `->'), and a full
duplex socket shows a double arrow (`<->').
When the -s flag is used, socket endpoint information is shown after the
address of the socket. For internet sockets the local and remote
addresses are shown, separated with a double arrow (`<->'). For
UNIX/local sockets either the local or remote address is shown, depending
on which one is available.
EXIT STATUS
The fstat utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
Show all open files except those opened by fstat itself:
$ fstat | awk '$2 != "fstat"'
USER CMD PID FD MOUNT INUM MODE SZ|DV R/W
alice bash 469 text /usr/local 143355 -rwxr-xr-x 1166448 r
alice bash 469 ctty /dev 346 crw--w---- pts/81 rw
...
Report all files opened by the current shell in the same file system as
/usr/local including memory-mapped files:
$ fstat -m -p $$ -f /usr/local
USER CMD PID FD MOUNT INUM MODE SZ|DV R/W
bob bash 469 text /usr/local 143355 -rwxr-xr-x 1166448 r
bob bash 469 mmap /usr/local 143355 -rwxr-xr-x 1166448 r
...
Requesting information about a file that is not opened results in just a
header line instead of an error:
$ fstat /etc/rc.conf
USER CMD PID FD MOUNT INUM MODE SZ|DV R/W NAME
All parameters after -f will be interpreted as files, so the following
will not work as expected:
$ fstat -f /usr/local -m -p $$
fstat: -m: No such file or directory
fstat: -p: No such file or directory
fstat: 469: No such file or directory
...
Show number of pipes opened by firefox processes:
$ fstat | awk '$2=="firefox" && $5=="pipe"' | wc -l
Show processes belonging to user "bob" whose standard error descriptor is
opened in ttyv0:
$ fstat -u bob | awk '$4 == 2 && $8 == "ttyv0"'
bob firefox 77842 2 /dev 103 crw------- ttyv0 rw
bob xinit 1194 2 /dev 103 crw------- ttyv0 rw
...
Show opened TCP sockets. This output resembles the one produced by
`netstat -A -p tcp' :
$ fstat | awk '$7 == "tcp"'
alice firefox 77991 32* internet stream tcp fffff800b7f147a0
alice firefox 77991 137* internet stream tcp fffff800b7f12b70
...
Show a list of processes with files opened in the current directory
mimicking the output of fuser(1) :
$ fstat . | awk 'NR > 1 {printf "%d%s(%s) ", $3, $4, $1;}'
2133wd(alice) 2132wd(alice) 1991wd(alice)
Create a list of processes sorted by number of opened files in desdencing
order:
$ fstat | awk 'NR > 1 {print $2;}' | sort | uniq -c | sort -r
728 firefox
23 bash
14 sort
8 fstat
7 awk
SEE ALSO
fuser(1), netstat(1), nfsstat(1), procstat(1), ps(1), sockstat(1),
systat(1), tcp(4), unix(4), iostat(8), pstat(8), vmstat(8)
HISTORY
The fstat command appeared in 4.3BSD-Tahoe.
BUGS
Since fstat takes a snapshot of the system, it is only correct for a very
short period of time.
FreeBSD 13.1-RELEASE-p6 November 19, 2020 FreeBSD 13.1-RELEASE-p6
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