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NSYSCTL(8)		     System Manager's Manual		      NSYSCTL(8)

NAME
     nsysctl -- get or set system state

SYNOPSIS
     nsysctl [--libxo options [-r tagroot]] [-DdeFGgHIiJLnOpqTtVvWz]
	     [-N | -hl [b | o | x]] [-B bufsize] [-f filename] [-j jailname]
	     [-s sep] name[=value[,value]] ...
     nsysctl [--libxo options [-r tagroot]] [-DdeFGgHIJkLnOpqSTtVvWz]
	     [-N | -hlu [b | o | x]] [-B bufsize] [-f filename] [-j jailname]
	     [-s sep] -a

DESCRIPTION
     The  nsysctl  utility is used to get or set the state of the system at run-
     time.

     The system exposes the available parameters as  objects  in  a  "Management
     Information Base" (MIB).  nsysctl can explore the MIB, print object proper-
     ties, retrieve or update their values, and display the output in both human
     and machine readable formats.

     Each  object  is identified by an "Object Identifier" (OID), which is a se-
     quence of numbers.  Numbers can be replaced with strings to form the object
     name.  For example, "1.1" can be expressed as "kern.ostype".

     nsysctl accepts one or more object names,	optionally  followed  by  a  new
     value.  Alternatively, the -a flag can be used to display all available ob-
     jects.

     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 using libxo(3) in a variety of  human  and  machine
	     readable formats.	See xo_parse_args(3) for supported options.

     -A      Equivalent to -a -o.  This option is obsolete.

     -a      Display all objects.

     -b      Print values in binary format.

     -B bufsize
	     Use a buffer of bufsize bytes.

     -D      Equivalent to -d -F -G -H -L -O -t.

     -d      Show object descriptions.

     -e      Use "=" as a key-value separator.

     -F      Display the format string of each object.

     -f filename
	     Load object names from filename.

     -G      Show flags with their true (internal) values.

     -g      Display flags associated with each object.

     -H      Show the handler status of each object.

     -h      Attempt to display values in a human-friendly format.

     -I      Include  internal nodes in the output.  By default, only leaf nodes
	     are shown.

     -i      Ignore unknown objects.

     -J      Show only objects flagged with PRISON.  See jail(2) for details.

     -j jailname
	     Attach to the jail named jailname.  See jail(2) and jls(8) for  de-
	     tails.   nsysctl initializes libxo(3), parses command-line options,
	     and attaches to the specified jail immediately afterward.	Any file
	     specified with  the  -f  option  is  read	within	the  context  of
	     jailname.	See jexec(8) for additional jail execution methods.

     -k      Include objects marked with the SKIP flag when used with -a.

     -L      Display the aggregation label.

     -l      Display the size of the value in bytes.

     -N      Suppress value output.

     -n      Suppress name output.

     -O      Display the Object Identifier (OID).

     -o      Display values in hexadecimal format, up to 16 bytes.

     -p      Display   property   output   in	the   format:  "[PROPERTY-NAME]:
	     property-value".

     -q      Suppress certain warnings.

     -r tagroot
	     Specify a tagroot for use with libxo(3).

     -S      Also display the "sysctl.*" subtree when used with -a.

     -s sep  Use sep as a separator.

     -T      Show only objects that are settable via the loader.

     -t      Display the type of each object.

     -u      By default, -a hides objects without a value.  This option disables
	     that behavior.

     -V      Show only objects relevant  to  network  subsystem  virtualization,
	     flagged with VNET.  See vnet(9) for details.

     -v      Display the nsysctl version and exit.

     -W      Show only writable objects that are not marked as statistical.

     -X      Equivalent to -a -x.  This option is obsolete.

     -x      Display values in hexadecimal format.

     -z      Toggle  the  numeric or boolean value.  A value of 0 becomes 1, and
	     any non-zero value becomes 0.  Only the first element of  an  array
	     is modified.

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

EXAMPLES
     To retrieve the value of an object:

	   % nsysctl kern.hostname

     To set the value of an object:

	   % nsysctl kern.hostname=myBSD

     To display detailed information about an object:

	   % nsysctl -pD kern.ostype

     To display object information in XML format:

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

COMPATIBILITY
     sysctl(8)	prints	internal and SKIP nodes when used with -aN, -ad, or -at.
     Otherwise, it only prints leaf nodes, skipping those marked with SKIP.

     To reproduce the same behavior with nsysctl, use the following equivalents:
	   /sbin/sysctl 	    /usr/local/sbin/nsysctl
	   % sysctl -aN 	    % nsysctl -aNIk
	   % sysctl -ad 	    % nsysctl -adIk
	   % sysctl -at 	    % nsysctl -atIk

SEE ALSO
     jail(2),  sysctl(3),  sysctlmibinfo2(3),  xo_parse_args(3),  sysctlinfo(4),
     jexec(8), jls(8), sysctl(8)

AUTHORS
     nsysctl was written by Alfonso Sabato Siciliano <asiciliano@FreeBSD.org>.

FreeBSD ports 15.quarterly	  June 28, 2025 		      NSYSCTL(8)

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