---
name: "backlight"
section: "8"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/backlight"
---

# backlight(8)

configure backlight hardware

## 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)](/rc.conf/5.md). 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
```

## SEE ALSO

[backlight(9)](/backlight/9.md)

## HISTORY

The **backlight** utility appeared in FreeBSD 13.0.

## AUTHORS

The **backlight** utility and this manual page were written by Emmanuel Vadot ⟨*manu@FreeBSD.org*⟩.