SYSTAT(1) BSD General Commands Manual SYSTAT(1)NAMEsystat — display system statistics
SYNOPSISsystat [-display] [refresh-interval]
The systat utility displays various system statistics in a screen ori‐
ented fashion using the curses screen display library, ncurses(3).
While systat is running the screen is usually divided into two windows
(an exception is the vmstat display which uses the entire screen). The
upper window depicts the current system load average. The information
displayed in the lower window may vary, depending on user commands. The
last line on the screen is reserved for user input and error messages.
By default systat displays the processes getting the largest percentage
of the processor in the lower window. Other displays show swap space
usage, disk I/O statistics (a la iostat(8)), virtual memory statistics (a
la vmstat(8)), network ``mbuf'' utilization, TCP/IP statistics, and net‐
work connections (a la netstat(1)).
Input is interpreted at two different levels. A ``global'' command
interpreter processes all keyboard input. If this command interpreter
fails to recognize a command, the input line is passed to a per-display
command interpreter. This allows each display to have certain display-
Command line options:
-display The - flag expects display to be one of: icmp, icmp6,
ifstat, iostat, ip, ip6, mbufs, netstat, pigs, swap,
tcp, or vmstat. These displays can also be requested
interactively (without the “-”) and are described in
full detail below.
refresh-interval The refresh-value specifies the screen refresh time
interval in seconds.
Certain characters cause immediate action by systat. These are
^L Refresh the screen.
^G Print the name of the current ``display'' being shown in the
lower window and the refresh interval.
: Move the cursor to the command line and interpret the input
line typed as a command. While entering a command the cur‐
rent character erase, word erase, and line kill characters
may be used.
The following commands are interpreted by the ``global'' command inter‐
help Print the names of the available displays on the command
load Print the load average over the past 1, 5, and 15 minutes on
the command line.
stop Stop refreshing the screen.
Start (continue) refreshing the screen. If a second,
numeric, argument is provided it is interpreted as a refresh
interval (in seconds). Supplying only a number will set the
refresh interval to this value.
quit Exit systat. (This may be abbreviated to q.)
The available displays are:
pigs Display, in the lower window, those processes resident in
main memory and getting the largest portion of the processor
(the default display). When less than 100% of the processor
is scheduled to user processes, the remaining time is
accounted to the ``idle'' process.
icmp Display, in the lower window, statistics about messages
received and transmitted by the Internet Control Message Pro‐
tocol (“ICMP”). The left half of the screen displays infor‐
mation about received packets, and the right half displays
information regarding transmitted packets.
The icmp display understands two commands: mode and reset.
The mode command is used to select one of four display modes,
given as its argument:
rate: show the rate of change of each value in packets
(the default) per second
delta: show the rate of change of each value in packets
per refresh interval
since: show the total change of each value since the
display was last reset
absolute: show the absolute value of each statistic
The reset command resets the baseline for since mode. The
mode command with no argument will display the current mode
in the command line.
icmp6 This display is like the icmp display, but displays statis‐
tics for IPv6 ICMP.
ip Otherwise identical to the icmp display, except that it dis‐
plays IP and UDP statistics.
ip6 Like the ip display, except that it displays IPv6 statics.
It does not display UDP statistics.
tcp Like icmp, but with TCP statistics.
iostat Display, in the lower window, statistics about processor use
and disk throughput. Statistics on processor use appear as
bar graphs of the amount of time executing in user mode
(``user''), in user mode running low priority processes
(``nice''), in system mode (``system''), in interrupt mode
(``interrupt''), and idle (``idle''). Statistics on disk
throughput show, for each drive, megabytes per second, aver‐
age number of disk transactions per second, and average kilo‐
bytes of data per transaction. This information may be dis‐
played as bar graphs or as rows of numbers which scroll down‐
ward. Bar graphs are shown by default.
The following commands are specific to the iostat display;
the minimum unambiguous prefix may be supplied.
numbers Show the disk I/O statistics in numeric form.
Values are displayed in numeric columns which
bars Show the disk I/O statistics in bar graph form
kbpt Toggle the display of kilobytes per transaction.
(the default is to not display kilobytes per
swap Show information about swap space usage on all the swap areas
compiled into the kernel. The first column is the device
name of the partition. The next column is the total space
available in the partition. The Used column indicates the
total blocks used so far; the graph shows the percentage of
space in use on each partition. If there are more than one
swap partition in use, a total line is also shown. Areas
known to the kernel, but not in use are shown as not avail‐
mbufs Display, in the lower window, the number of mbufs allocated
for particular uses, i.e., data, socket structures, etc.
vmstat Take over the entire display and show a (rather crowded) com‐
pendium of statistics related to virtual memory usage,
process scheduling, device interrupts, system name transla‐
tion caching, disk I/O etc.
The upper left quadrant of the screen shows the number of
users logged in and the load average over the last one, five,
and fifteen minute intervals. Below this line are statistics
on memory utilization. The first row of the table reports
memory usage only among active processes, that is processes
that have run in the previous twenty seconds. The second row
reports on memory usage of all processes. The first column
reports on the number of kilobytes in physical pages claimed
by processes. The second column reports the number of kilo‐
bytes in physical pages that are devoted to read only text
pages. The third and fourth columns report the same two fig‐
ures for virtual pages, that is the number of kilobytes in
pages that would be needed if all processes had all of their
pages. Finally the last column shows the number of kilobytes
in physical pages on the free list.
Below the memory display is a list of the average number of
processes (over the last refresh interval) that are runnable
(`r'), in page wait (`p'), in disk wait other than paging
(`d'), sleeping (`s'), and swapped out but desiring to run
(`w'). The row also shows the average number of context
switches (`Csw'), traps (`Trp'; includes page faults), system
calls (`Sys'), interrupts (`Int'), network software inter‐
rupts (`Sof'), and page faults (`Flt').
Below the process queue length listing is a numerical listing
and a bar graph showing the amount of system (shown as `='),
interrupt (shown as `+'), user (shown as `>'), nice (shown as
`-'), and idle time (shown as ` ').
Below the process display are statistics on name transla‐
tions. It lists the number of names translated in the previ‐
ous interval, the number and percentage of the translations
that were handled by the system wide name translation cache,
and the number and percentage of the translations that were
handled by the per process name translation cache.
To the right of the name translations display are lines show‐
ing the number of dirty buffers in the buffer cache
(`dtbuf'), desired maximum size of vnode cache (`desvn'),
number of vnodes actually allocated (`numvn'), and number of
allocated vnodes that are free (`frevn').
At the bottom left is the disk usage display. It reports the
number of kilobytes per transaction, transactions per second,
megabytes per second and the percentage of the time the disk
was busy averaged over the refresh period of the display (by
default, five seconds). The system keeps statistics on most
every storage device. In general, up to seven devices are
displayed. The devices displayed by default are the first
devices in the kernel's device list. See devstat(3) and
devstat(9) for details on the devstat system.
Under the date in the upper right hand quadrant are statis‐
tics on paging and swapping activity. The first two columns
report the average number of pages brought in and out per
second over the last refresh interval due to page faults and
the paging daemon. The third and fourth columns report the
average number of pages brought in and out per second over
the last refresh interval due to swap requests initiated by
the scheduler. The first row of the display shows the aver‐
age number of disk transfers per second over the last refresh
interval; the second row of the display shows the average
number of pages transferred per second over the last refresh
Below the paging statistics is a column of lines regarding
the virtual memory system. The first few lines describe, in
units (except as noted below) of pages per second averaged
over the sampling interval, pages copied on write (`cow'),
pages zero filled on demand (`zfod'), pages optimally zero
filled on demand (`ozfod'), the ratio of the (average) ozfod
/ zfod as a percentage (`%ozfod'), pages freed by the page
daemon (`daefr'), pages freed by exiting processes (`prcfr'),
total pages freed (`totfr'), pages reactivated from the free
list (`react'), the average number of times per second that
the page daemon was awakened (`pdwak'), pages analyzed by the
page daemon (`pdpgs'), and in-transit blocking page faults
(`intrn'). Note that the units are special for `%ozfod' and
`pdwak'. The next few lines describe, as amounts of memory
in kilobytes, pages wired down (`wire'), active pages
(`act'), inactive pages (`inact'), pages on the cache queue
(`cache'), and free pages (`free'). Note that the values
displayed are the current transient ones; they are not aver‐
At the bottom of this column is a line showing the amount of
virtual memory, in kilobytes, mapped into the buffer cache
(`buf'). This statistic is not useful. It exists only as a
placeholder for the corresponding useful statistic (the
amount of real memory used to cache disks). The most impor‐
tant component of the latter (the amount of real memory used
by the vm system to cache disks) is not available, but can be
guessed from the `inact' amount under some system loads.
Running down the right hand side of the display is a break‐
down of the interrupts being handled by the system. At the
top of the list is the total interrupts per second over the
time interval. The rest of the column breaks down the total
on a device by device basis. Only devices that have inter‐
rupted at least once since boot time are shown.
The following commands are specific to the vmstat display;
the minimum unambiguous prefix may be supplied.
boot Display cumulative statistics since the system
run Display statistics as a running total from the
point this command is given.
time Display statistics averaged over the refresh
interval (the default).
zero Reset running statistics to zero.
netstat Display, in the lower window, network connections. By
default, network servers awaiting requests are not displayed.
Each address is displayed in the format ``host.port'', with
each shown symbolically, when possible. It is possible to
have addresses displayed numerically, limit the display to a
set of ports, hosts, and/or protocols (the minimum unambigu‐
ous prefix may be supplied):
all Toggle the displaying of server processes
awaiting requests (this is the equivalent of
the -a flag to netstat(1)).
numbers Display network addresses numerically.
names Display network addresses symbolically.
Display only network connections using the
indicated protocol. Supported protocols are
``tcp'', ``udp'', and ``all''.
Do not display information about connections
associated with the specified hosts or ports.
Hosts and ports may be specified by name
(``vangogh'', ``ftp''), or numerically. Host
addresses use the Internet dot notation
(``184.108.40.206''). Multiple items may be speci‐
fied with a single command by separating them
Display information about the connections asso‐
ciated with the specified hosts or ports. As
for ignore, [items] may be names or numbers.
Show, on the command line, the currently
selected protocols, hosts, and ports. Hosts
and ports which are being ignored are prefixed
with a `!'. If ports or hosts is supplied as
an argument to show, then only the requested
information will be displayed.
reset Reset the port, host, and protocol matching
mechanisms to the default (any protocol, port,
ifstat Display the network traffic going through active interfaces
on the system. Idle interfaces will not be displayed until
they receive some traffic.
For each interface being displayed, the current, peak and
total statistics are displayed for incoming and outgoing
traffic. By default, the ifstat display will automatically
scale the units being used so that they are in a human-read‐
able format. The scaling units used for the current and peak
traffic columns can be altered by the scale command.
scale [units] Modify the scale used to display the current
and peak traffic over all interfaces. The
following units are recognised: kbit, kbyte,
mbit, mbyte, gbit, gbyte and auto.
Commands to switch between displays may be abbreviated to the minimum
unambiguous prefix; for example, ``io'' for ``iostat''. Certain informa‐
tion may be discarded when the screen size is insufficient for display.
For example, on a machine with 10 drives the iostat bar graph displays
only 3 drives on a 24 line terminal. When a bar graph would overflow the
allotted screen space it is truncated and the actual value is printed
``over top'' of the bar.
The following commands are common to each display which shows information
about disk drives. These commands are used to select a set of drives to
report on, should your system have more drives configured than can nor‐
mally be displayed on the screen.
Do not display information about the drives indicated.
Multiple drives may be specified, separated by spaces.
Display information about the drives indicated. Multiple
drives may be specified, separated by spaces.
Display only the specified drives. Multiple drives may be
specified, separated by spaces.
drives Display a list of available devices.
match type,if,pass [| ...]
Display devices matching the given pattern. The basic
matching expressions are the same as those used in
iostat(8) with one difference. Instead of specifying mul‐
tiple -t arguments which are then ORed together, the user
instead specifies multiple matching expressions joined by
the pipe (‘|’) character. The comma separated arguments
within each matching expression are ANDed together, and
then the pipe separated matching expressions are ORed
together. Any device matching the combined expression will
be displayed, if there is room to display it. For example:
match da,scsi | cd,ide
This will display all SCSI Direct Access devices and all
IDE CDROM devices.
match da | sa | cd,pass
This will display all Direct Access devices, all Sequential
Access devices, and all passthrough devices that provide
access to CDROM drives.
/boot/kernel/kernel For the namelist.
/dev/kmem For information in main memory.
/etc/hosts For host names.
/etc/networks For network names.
/etc/services For port names.
SEE ALSOnetstat(1), kvm(3), icmp(4), icmp6(4), ip(4), ip6(4), tcp(4), udp(4),
gstat(8), iostat(8), vmstat(8)HISTORY
The systat program appeared in 4.3BSD. The icmp, ip, and tcp displays
appeared in FreeBSD 3.0; the notion of having different display modes for
the ICMP, IP, TCP, and UDP statistics was stolen from the -C option to
netstat(1) in Silicon Graphics' IRIX system.
Certain displays presume a minimum of 80 characters per line. The vmstat
display looks out of place because it is (it was added in as a separate
display rather than created as a new program).
BSD October 14, 2007 BSD