backlight.1

Sun, 09 Feb 2020 10:53:55 +0100

author
David Demelier <markand@malikania.fr>
date
Sun, 09 Feb 2020 10:53:55 +0100
changeset 20
232b390f1682
parent 19
0de3886f98ad
child 23
6081cc143d37
permissions
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doc: minor typo

.\"
.\" Copyright (c) 2010-2020 David Demelier <markand@malikania.fr>
.\"
.\" Permission to use, copy, modify, and/or distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd September 16, 2019
.Dt BACKLIGHT 1
.Os
.\" NAME
.Sh NAME
.Nm backlight
.Nd adjust screen brightness
.\" SYNOPSIS
.Sh SYNOPSIS
.Nm
.Ar decrease
.Nm
.Ar get
.Nm
.Ar increase
.Nm
.Ar set
.Ar percentage
.\" DESCRIPTION
.Sh DESCRIPTION
The
.Nm
tool adjust the brightness on your screen using direct access to ACPI video
extension.
.Pp
The following commands are available:
.Bl -tag -width 10n
.It Cm decrease
Decrease to the next lower level.
.It Cm get
Get the current level scaled to a percentage range.
.It Cm increase
Increase to the next upper level.
.It Cm set
Set brightness to the
.Ar percentage
value.
.El
.\" SYSTEM SUPPORT
.Sh SYSTEM SUPPORT
.Ss Linux
On Linux, you need to have ACPI Video support either as module or built-in the
kernel.
.Pp
You may use
.Nm
as non-root user if you create appropriate udev rules to make files under
.Pa /sys/class/backlight
writable by a group or per user.
.Pp
The source package comes with an example of udev rule that can be installed in
.Pa /usr/lib/udev/rules.d .
.Ss FreeBSD
Access to brightness under FreeBSD requires super-user, you may need to run
.Nm
as root or use setuid permission for non-root users.
.Pp
You also need to load
.Xr acpi_video 4
module at boot by adding
.Sy acpi_video_load="YES"
in
.Pa /boot/loader.conf .
.\" AUTHORS
.Sh AUTHORS
.Nm
was written by David Demelier <markand@malikania.fr>

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