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67,586
Votes: 5
Tags:
16.04
multiple-monitors
brightness
hdmi
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🔍 See Original Answer on Ask Ubuntu ⧉ 🔗
URL:
https://askubuntu.com/q/1150416
Title:
Changing the screen brightness of the external screen
ID:
/2019/06/12/Changing-the-screen-brightness-of-the-external-screen
Created:
June 12, 2019
Edited: June 12, 2020
Upload:
September 15, 2024
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Rather than plugging in a brightness level for xrandr you can use this bash script to adjust the brightness up or down in steps.
Copy bash script below to a file called bright
Then mark it executable with chmod a+x bright
Bash Script
#!/bin/bash
MON="DP-1-1" # Discover monitor name with: xrandr | grep " connected"
STEP=5 # Step Up/Down brightnes by: 5 = ".05", 10 = ".10", etc.
CurrBright=$( xrandr --verbose --current | grep ^"$MON" -A5 | tail -n1 )
CurrBright="${CurrBright##* }" # Get brightness level with decimal place
Left=${CurrBright%%"."*} # Extract left of decimal point
Right=${CurrBright#*"."} # Extract right of decimal point
MathBright="0"
[[ "$Left" != 0 && "$STEP" -lt 10 ]] && STEP=10 # > 1.0, only .1 works
[[ "$Left" != 0 ]] && MathBright="$Left"00 # 1.0 becomes "100"
[[ "${#Right}" -eq 1 ]] && Right="$Right"0 # 0.5 becomes "50"
MathBright=$(( MathBright + Right ))
[[ "$1" == "Up" || "$1" == "+" ]] && MathBright=$(( MathBright + STEP ))
[[ "$1" == "Down" || "$1" == "-" ]] && MathBright=$(( MathBright - STEP ))
[[ "${MathBright:0:1}" == "-" ]] && MathBright=0 # Negative not allowed
[[ "$MathBright" -gt 999 ]] && MathBright=999 # Can't go over 9.99
if [[ "${#MathBright}" -eq 3 ]] ; then
MathBright="$MathBright"000 # Pad with lots of zeros
CurrBright="${MathBright:0:1}.${MathBright:1:2}"
else
MathBright="$MathBright"000 # Pad with lots of zeros
CurrBright=".${MathBright:0:2}"
fi
xrandr --output "$MON" --brightness "$CurrBright" # Set new brightness
# Display current brightness
printf "Monitor $MON "
echo $( xrandr --verbose --current | grep ^"$MON" -A5 | tail -n1 )
- Change
MON="DP-1-1"to your monitor name, ieMON="eDP-1-1" - Change
STEP=5to your step value, egSTEP=2is less noticeable
Call the script with:
bright Uporbright +to increase brightness by step valuebright Downorbright -to decrease brightness by step valuebright(with no parameters) to get the current brightness level
Hopefully the bash / shell commands can easily be googled for education but if any questions don’t hesitate to ask :)