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KENV(1)			FreeBSD	General	Commands Manual		       KENV(1)

NAME
     kenv -- list or modify the	kernel environment

SYNOPSIS
     kenv [-l |	-s] [-hNq]
     kenv [-qv]	variable[=value]
     kenv [-q] -u variable

DESCRIPTION
     The kenv utility will list	all variables in the kernel environment	if in-
     voked without arguments.

     If	the -l option is specified, then the static environment	provided by
     loader(8) will be listed instead.	Similarly, the -s option will list the
     static environment	defined	by the kernel config.  Both of the -l and -s
     options are dependent on the kernel being configured to preserve early
     kernel environments.  The default kernel configuration does not preserve
     these environments.

     If	the -h option is specified, it will limit the report to	kernel probe
     hints.  If	an optional variable name is specified,	kenv will only report
     that value.  If the -N option is specified, kenv will only	display	vari-
     able names	and not	their values.  If the -u option	is specified, kenv
     will delete the given environment variable.  If the environment variable
     is	followed by an optional	value, kenv will set the environment variable
     to	this value.

     If	the -q option is set, warnings normally	printed	as a result of being
     unable to perform the requested operation will be suppressed.

     If	the -v option is set, the variable name	will be	printed	out for	the
     environment variable in addition to the value when	kenv is	executed with
     a variable	name.

     Variables can be added to the kernel environment using the
     /boot/loader.conf file, or	also statically	compiled into the kernel using
     the statement

	   env filename

     in	the kernel config file.	 The file can contain lines of the form

	   name	= value	# this is a comment

     where whitespace around `name' and	`=', and everything after a `#'	char-
     acter, are	ignored.  Almost any printable character except	`=' is accept-
     able as part of a name.  Quotes are optional and necessary	only if	the
     value contains whitespace.

EXAMPLES
     Show kernel probe hints variable names and	filter for the uart device

	   $ kenv -h -N	| grep uart
	   hint.uart.0.at
	   hint.uart.0.flags
	   hint.uart.0.irq
	   hint.uart.0.port
	   hint.uart.1.at
	   hint.uart.1.irq
	   hint.uart.1.port

     Show the value of a specific variable:

	   $ kenv hint.uart.1.at
	   isa

     Same as above but adding the name of the variable in the report:

	   $ kenv -v hint.uart.1.at
	   hint.uart.1.at="isa"

     Try to delete a variable and suppress warnings if any:

	   $ kenv -q -u	hint.uart.1.at

     Set the value of the verbose_loading variable

	   $ kenv verbose_loading="YES"
	   verbose_loading="YES"

SEE ALSO
     kenv(2), config(5), loader.conf(5), loader(8)

HISTORY
     The kenv utility appeared in FreeBSD 4.1.1.

FreeBSD	13.0			 June 20, 2021			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | HISTORY

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