displays various system statistics in a
screen-oriented fashion using the
is running, the screen is divided into
different areas. The top line displays the current number of users, the three
system load average figures over the last 1, 5, and 15 minute intervals, and
the system time. The bottom line of the screen is reserved for user input and
error messages. The information displayed in the rest of the screen comprises
, and is the main interface for displaying
different types of system statistics. The vmstat
view is the default.
Certain information may be discarded when the screen size is insufficient for
display. For example, on a machine with 10 drives the
bar graph displays only 3 drives on a 24
The options are as follows:
- Display all lines.
- Raw, non-interactive mode. The default is to exit after two
screen updates, with statistics only ever displayed once. Useful for views
such as cpu, where initial calculations are
- Raw, non-interactive mode. The default is to exit after one
screen update, with statistics displayed every update.
- Exit after count screen
- Interactive mode.
- Resolve network addresses to names. This is the opposite of
the -n option.
- Do not try to reverse map IP addresses. This is the
- Specifies the screen refresh time interval in seconds. This
option is overridden by the final delay
argument, if given. The default interval is 5 seconds.
- Specifies the maximum width of the output in raw,
- The view argument expects
to be one of: vmstat,
cpu. These displays can also be requested
interactively and are described in full detail below.
view may be abbreviated to the minimum
unambiguous prefix; for example, “io” for
- The delay argument
specifies the screen refresh time interval in seconds. This is provided
for backwards compatibility, and overrides any interval specified with the
-s flag. The default interval is 5
Certain characters cause immediate action by
. These are:
- Move the cursor to the command line and interpret the input
line typed as a command. While entering a command the current character
erase, word erase, and line kill characters may be used.
- Select the next ordering which sorts the rows according to
a combination of columns. Available orderings depend on the view. Not all
views support orderings.
- Pause systat.
- Quit systat.
- Reverse the selected ordering if supported by the
- Print numbers with thousand separators, where
- Jump to the beginning of the current view.
| ⟨right arrow⟩
- Select the previous view.
- Jump to the end of the current view.
| ⟨left arrow⟩
- Select the next view.
- Print the name of the current view being shown and the
- Refresh the screen.
| ⟨down arrow⟩
- Scroll current view down by one line.
| ⟨up arrow⟩
- Scroll current view up by one line.
| ⟨Page Down⟩
- Scroll current view down by one page.
| ⟨Page Up⟩
- Scroll current view up by one page.
- Suspend systat.
The following commands are interpreted by the “global” command
- Print the names of the available views on the command
- Quit systat. (This may be
abbreviated to q.)
- 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
may be abbreviated to the minimum
unambiguous prefix. The available views are:
- Display kernel
statistics similar to the output of vmstat
- Display information about the average usage of each CPU,
similar to the output provided by
- Display interface statistics. The “State”
column has the format
‘up’ and ‘dn’ represent whether the interface
is up or down. ‘U’ and ‘D’ represent whether
the interface is connected or not; in the case of
interfaces, whether the interface is in master or backup state,
The character B changes the counter view
between bytes and bits. Pressing b displays
statistics as calculated from boot time. r
changes the counters to show their totals as calculated between display
refreshes. t changes the counters to show the
average per second over the display refresh interval; this is the
- Display statistics about disk throughput. Statistics on
disk throughput show, for each drive, data transferred in kilobytes,
number of disk transactions performed, and time spent in disk accesses (in
fractions of a second).
- Display kernel
statistics similar to the output of vmstat
-m. Available orderings are:
- Display mbuf usage information from kernel pools and mbuf
cluster pool statistics of each network interface.
- Display network connections. Each address is displayed
numerically in the format “host:port”. By default, network
servers awaiting requests are not displayed. It is also possible to have
addresses displayed symbolically, when possible, and limit the display to
a set of protocols (the minimum unambiguous prefix may be supplied):
- Toggle the displaying of server processes awaiting
requests (this is the equivalent of the
-a flag to
- Display network addresses symbolically.
- Display network addresses numerically.
- Reset matching mechanisms to the default.
- Display only network connections using the indicated
- Display statistics about NFS client activity. Output
- Display statistics about NFS server activity. Output
- Display filter information about
pf(4), similar to
the output of pfctl
- Display those processes resident in main memory and getting
the largest portion of the processor. When less than 100% of the processor
is scheduled to user processes, the remaining time is accounted to the
- Display kernel
similar to the output of vmstat
-m. Available orderings are:
size, and number of
By default only the statistics of active pools are displayed but pressing
A changes the view to show all of them.
- Display statistics about the active queues, similar to the
output of pfctl
- Display pf rules statistics, similar to the output of
- Display the current values of available hardware sensors,
in a format similar to that of
- Display pf states statistics, similar to the output of
states. Available orderings are:
address, source port,
rate, and peak
- 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 is 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
- Take over the entire display and show a (rather crowded)
compendium of statistics related to virtual memory usage, process
scheduling, device interrupts, system name translation caching, disk I/O,
etc. This view is the default.
Below the top 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
amount of physical memory claimed by processes. The second column reports
the same figure for virtual memory, that is, the amount of memory that
would be needed if all processes were resident at the same time. Finally,
the last column shows the amount of physical memory 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 disk
wait other than paging (‘d’), sleeping (‘s’),
and swapped out but desiring to run (‘w’). Below the queue
length listing is a numerical listing and a bar graph showing the amount
of interrupt (shown as ‘
(shown as ‘
=’), user (shown as
>’), nice (shown as
-’), and idle time (shown as
To the right of the Proc display are statistics about Context switches
(“Csw”), Traps (“Trp”), Syscalls
(“Sys”), Interrupts (“Int”), Soft interrupts
(“Sof”), and Faults (“Flt”) which have
occurred during the last refresh interval.
Below the CPU usage graph are statistics on name translations. It lists the
number of names translated in the previous 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.
At the bottom left is the disk usage display. It reports the number of
seeks, transfers, number of kilobyte blocks transferred per second
averaged over the refresh period of the display, and the time spent in
Under the date in the upper right hand quadrant are statistics 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 average 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
Running down the right hand side of the display is a breakdown 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
interrupted at least once since boot time are shown.
Below the Interrupts display are the average number of input and output
packets per second for all interfaces over the last refresh interval.
Below the SWAPPING display and slightly to the left of the Interrupts
display is a list of virtual memory statistics. The abbreviations are:
- process forks
- forks where parent waits
- forks where vmspace is shared
- fault had to wait on a page
- fault relock called
- fault relock is successful
- faults out of ram
- number of times fault clears "need copy"
- number of times fault promotes with copy
- fault promotes with zerofill
- number of times fault anon cow
- min number of free pages
- target number of free pages
- target number of inactive pages
- wired pages
- pages daemon freed since boot
- pages daemon scanned since boot
- number of zeroed pages
- number of kernel map entries
- Host names.
- Port names.
program first appeared in
Certain displays presume a minimum of 80 characters per line. The
display looks out of place because it is
(it was added in as a separate display rather than created as a new