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KENV(1)			    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
       invoked 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  re-
       port that value.	 If the	-N option is specified,	kenv will only display
       variable	 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 environ-
       ment 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 us-
       ing 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 `#'
       character, are ignored.	Almost any printable character except  `='  is
       acceptable  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	ports 15.quarterly	 June 20, 2021			       KENV(1)

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