backlight(8)

NAME

backlight – configure backlight hardware

SYNOPSIS

backlight [-q] [-f device]

backlight [-q] [-f device] -i

backlight [-f device] value

backlight [-f device] incr|+ [value]

backlight [-f device] decr|- [value]

DESCRIPTION

The backlight utility can be used to configure brightness levels for registered backlights.

Called without any arguments it will print the current brightness level of the first registered backlight.

The options are as follows:

-f device: Device to operate on. If not specified, /dev/backlight/backlight0 is used. If an unqualified name is provided, /dev/backlight/ is automatically prepended.
-i: Query information about the backlight (name, type).
-q: When querying the brightness level only print the value.
value: Set the brightness level to this value, must be between 0 and 100. A trailing “%” is valid.
incr|+ [value]: Increment the backlight level. If no value is specified a default of 10 percent is used.
decr|- [value]: Decrement the backlight level. If no value is specified a default of 10 percent is used.

Brightness levels may not be preserved across a reboot unless backlight_enable is set to “YES” in rc.conf(5). This is disabled by default to avoid intefering with desktop environments that do their own backlight management.

EXAMPLES

Show the current brightness level:

$ backlight -f /dev/backlight/backlight0
brightness: 98

HISTORY

The backlight utility appeared in FreeBSD 13.0.

AUTHORS

The backlight utility and this manual page were written by Emmanuel Vadot ⟨[email protected]⟩.