bin/backlight: flesh out

1 files changed, 18 insertions, 4 deletions

diff --git a/.local/bin/backlight b/.local/bin/backlight
index 0657030..cf48dca 100755
--- a/.local/bin/backlight
+++ b/.local/bin/backlight
@@ -1,6 +1,20 @@
 #!/bin/bash
 
-backlight=intel_backlight
-pct=$1
-read max < /sys/class/backlight/$backlight/max_brightness
-bc <<<"scale=2; $max * ($pct/100)" | cut -d. -f1 > /sys/class/backlight/$backlight/brightness
+[[ -n "$BACKLIGHT" ]] || BACKLIGHT=intel_backlight
+fmax=/sys/class/backlight/$BACKLIGHT/max_brightness
+fcur=/sys/class/backlight/$BACKLIGHT/brightness
+read max < $fmax || exit $?
+case $# in
+	0)
+		read cur < $fcur
+		bc <<<"100*$cur/$max" | cut -d. -f1
+		;;
+	1)
+		declare -i pct="$1"
+		bc <<<"$max*$pct/100" | cut -d. -f1 > $fcur
+		;;
+	*)
+		echo "Usage: [BACKLIGHT=<device_id>] backlight [<percent>]" >&2
+		exit 1
+		;;
+esac