commit 5058511d7e34a1fd878aa1b9ff5dba2ff5e695dc
parent d509e43431397be44140915aced192ddc22b7c7d
Author: cowmonk <cowmonk@based.pt>
Date: Fri, 20 Mar 2026 06:20:22 +0000
Add Useful POSIX scripts
Moved scripts to files/bin since they are supposed to be installed into
`$PATH`.
- `backlight.sh` is for brightness, not great for multimonitor setups
though...
- `volume.sh` is mostly linux exclusive and just uses amixer, there's
nothing stopping the user from using alsa-utils directly, but it's
just for convience really
All scripts have been tested with `yash --posix` and with ubase/sbase.
It will work with literally any shell and any coreutils, so long as it's
linux. OpenBSD won't require these scripts at all, and it'll likely be
specified or whatever in the scripts.
Diffstat:
3 files changed, 157 insertions(+), 16 deletions(-)
diff --git a/files/bin/backlight.sh b/files/bin/backlight.sh
@@ -0,0 +1,136 @@
+#!/bin/sh
+#
+# useful script for backlight
+#
+
+usage()
+{
+ printf "\033[1musage:\033[0m %s [get|up|down|set] N%%\n" "$0"
+ printf "\tget\t\t\033[3mPrint current brightness percent\033[0m\n"
+ printf "\tup N\t\t\033[3mIncrease brightness by N percent\033[0m\n"
+ printf "\tdown N\t\t\033[3mDecrease brightness by N percent\033[0m\n"
+ printf "\tset N\t\t\033[3mSet brightness to N percent (0-100)\033[0m\n"
+ printf "\n\033[1m\033[91mWarning:\033[0m (or not really) if you have multiple backlights (multimonitor) then this script isn't for you.\n"
+ printf "\tConsider alternatives such as brightnessctl\n"
+}
+
+perms()
+{
+ printf "\033[91mPermission error:\033[0m Cannot access \`/sys/class/backlight/*/brightness\`"
+ printf "\nPlease set the perms to allow video group to access \`/sys/class/backlight/*/brightness\`:\n"
+ printf "\tchgrp video /sys/class/backlight/*/brightness\n"
+ printf "\tchmod 0660 /sys/class/backlight/*/brightness\n"
+ printf "\n\033[3mOptionally, you can set a udev/mdev rule to do this at boot (which is recommended)\033[0m\n"
+}
+
+# only finds the first one, which is why it's not recommended for multi-display setups
+find_backlight()
+{
+ for d in /sys/class/backlight/*; do
+ [ -e "$d" ] || continue
+ if [ -r "$d/max_brightness" ] && [ -w "$d/brightness" ]; then
+ printf '%s\n' "$d"
+ return 0
+ fi
+ done
+ return 1
+}
+
+dev=$(find_backlight) || {
+ perms
+ exit 2
+}
+bright_file="$dev/brightness"
+max_file="$dev/max_brightness"
+
+read_file() {
+ if [ ! -r "$1" ]; then
+ usage
+ exit 1
+ fi
+ IFS= read -r val <"$1" || return 1
+
+ case "$val" in
+ ''|*[!0-9]) return 1 ;;
+ *) printf '%s\n' "$val" ;;
+ esac
+}
+
+# max brightness in int
+max=$(read_file "$max_file") || {
+ printf '\033[91merror:\033[0m cannot read max_brightness\n' >&2
+ exit 3
+}
+# current brightness in int
+cur_int=$(read_file "$bright_file") || {
+ printf '\033[91merror:\033[0m cannot read brightness\n' >&2
+ exit 3
+}
+
+int_to_perc()
+{
+ int=$1
+ printf '%s\n' $(( (int * 100 + max/2) / max ))
+}
+
+perc_to_int()
+{
+ p=$1
+ if [ "$p" -le 0 ]; then
+ printf '0\n'
+ return
+ fi
+ if [ "$p" -ge 100 ]; then
+ printf '%s\n' "$max"
+ return
+ fi
+ printf '%s\n' $(( (p * max + 50) / 100 ))
+}
+
+cmd=${1:-}
+case "$cmd" in
+ get)
+ int_to_perc "$cur_int"
+ exit 0
+ ;;
+ up|down|set)
+ if [ -z "${2:-}" ]; then
+ usage
+ exit 1
+ fi
+ case "$2" in
+ ''|*[!0-9]) printf '\033[91merror:\033[0m N must be a non-negative integer\n' >&2; exit 1 ;;
+ esac
+ n=$2
+ ;;
+ *)
+ usage
+ exit 1
+ ;;
+esac
+
+# grab the current brightness
+cur_perc=$(int_to_perc "$cur_int")
+
+case "$cmd" in
+ set) target_perc=$n ;;
+ up) target_perc=$(( cur_perc + n )) ;;
+ down) target_perc=$(( cur_perc - n )) ;;
+esac
+
+# ensure values are never less than 0 or greater than 100
+if [ "$target_perc" -lt 0 ]; then target_perc=0; fi
+if [ "$target_perc" -gt 100 ]; then target_perc=100; fi
+
+target_int=$(perc_to_int "$target_perc") || {
+ printf '\033[91merror:\033[0m failed to compute target value\n' >&2
+ exit 4
+}
+
+if printf '%s' "$target_int" > "$bright_file"; then
+ printf '\033[1;32mok:\033[0m brightness set to %s%% (%s/%s)\n' "$target_perc" "$target_int" "$max"
+ exit 0
+else
+ perms
+ exit 5
+fi
diff --git a/files/bin/volume.sh b/files/bin/volume.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# useful volume script
+#
+
+usage()
+{
+ printf '\033[1mUsage: \033[0m%s [up|down|set|tog] N%%\n' "$0"
+ printf '\tup N\t\t\033[3mIncrease volume by N (e.g. %s up 5)\033[0m\n' "$0"
+ printf '\tdown N\t\t\033[3mDecrease volume by N\033[0m\n'
+ printf '\tset N\t\t\033[3mSet volume to N (0-100)\033[0m\n'
+ printf '\ttog\t\t\033[3mToggle mute\033[0m\n'
+}
+
+case "$1" in
+ up) amixer set Master ${2}%+ unmute ;;
+ down) amixer set Master ${2}%- ;;
+ tog) amixer set Master toggle ;;
+ set) amixer set Master ${2}% ;;
+ *) usage ;;
+esac
diff --git a/scripts/volume.sh b/scripts/volume.sh
@@ -1,16 +0,0 @@
-#!/bin/sh
-#
-# useful volume script
-#
-
-usage()
-{
- echo 'usage: volume.sh up|down|tog'
-}
-
-case "$1" in
- up) amixer set Master 5%+ unmute ;;
- down) amixer set Master 5%- ;;
- tog) amixer set Master toggle ;;
- *) usage ;;
-esac
