NAME

nsysctl —

get or set system state

SYNOPSIS

nsysctl [--libxo options [-r tagroot]] [-DdeFGgHIilnOpqTtvWz] [-N | -h [b | o | x]] [-B bufsize] [-s sep] [-f filename] name[=value[,value]] ...

nsysctl [--libxo options [-r tagroot]] [-DdeFGgHIklnOpqSTtvWz] [-N | -Vh [b | o | x]] [-B bufsize] [-s sep] -a

DESCRIPTION

The nsysctl utility can get or set the state of the System at runtime. The System exposes the available parameters as objects of a “Management Information Base” (MIB), nsysctl can explore the MIB, print the properties of an object, get or set its value and show the output in human and machine readable formats.

An object is identified by an Object Identifier (OID), a series of numbers, it is possible to replace a number with a string to obtain an object name, e.g., [1.1] → “kern.ostype”, nsysctl can receive in input one or more name, eventually with a new value, or -a for all objects.

nsysctl requires the sysctlinfo(4) interface. To load the required kernel module at boot time, place the following line in loader.conf(5):

sysctlinfo_load="YES"

The following options are available:

--libxo options: Generate output via libxo(3) in a selection of different human and machine readable formats, see xo_parse_args(3).
-A: Equivalent to -a -o, obsolete.
-a: Display all objects.
-b: Print value in binary format.
-B <bufsize>: use a buffer of <bufsize> bytes.
-D: Equivalent to -d -F -G -H -l -O -t.
-d: Show description.
-e: Use “=” as separator.
-F: Display format string.
-f <filename>: Load objects from <filename>.
-G: Show true flags.
-g: Print flags.
-H: Show the object handler status.
-h: Try to show values in a human-friendly format.
-I: Show internal nodes, only leaves are printed by default.
-i: Ignore unknown objects.
-k: Show object with SKIP flag with -a.
-l: Print aggregation label.
-m: Alias for -S.
-N: Hide value.
-n: Hide name.
-O: Display OID.
-o: Show value in hex format until 16 bytes.
-p: Display [ “PROPERTY-NAME” ]: “property-value”.
-q: Avoid to show some warning.
-r <tagroot>: Specify a <tagroot> with libxo.
-S: Display also the “sysctl.*” subtree with -a.
-s <sep>: Use <sep> as separator.
-T: Show only settable objects via loader.
-t: Print type.
-V: By default -a hides an object without a value, this option disable this feature.
-v: nsysctl version.
-W: Display only writable objects that are not statistical.
-X: Equivalent to -a -x, obsolete.
-x: Print value in hex format.
-y: Alias for -O.
-z: Toggle numeric or boolean value, if the value is 0 becomes 1, if it is not 0 becomes 0, if the value is an array only the first index takes effect.

EXIT STATUS

The nsysctl utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

To get an object value:

nsysctl kern.hostname

To set an object value:

nsysctl
  kern.hostname=myBSD

Print object info:

nsysctl -pD kern.ostype

Print object info in xml:

nsysctl --libxo=xml,pretty -D
  kern.ostype

COMPATIBILITY

sysctl(8) prints internal and SKIP nodes with -aN, -ad and -at, only leaves avoiding SKIP nodes otherwise, to reproduce with nsysctl:

/sbin/sysctl             /usr/local/sbin/nsysctl
% sysctl -aN             % nsysctl -aNIk
% sysctl -ad             % nsysctl -adIk
% sysctl -at             % nsysctl -atIk

HISTORY

The nsysctl utility first appeared in FreeBSD 13.0.

AUTHORS

nsysctl was written by Alfonso Sabato Siciliano <alf.siciliano@gmail.com>.