independ battery and volume

battery/Makefile

@@ -0,0 +1,20 @@
+all: ;
+clean: ;
+sane: ;
+
+dist: ../dist/battery.tar.gz
+
+../dist/battery: battery
+	mkdir -p ../dist/battery.tmp/bin/
+	cp battery* ../dist/battery.tmp/bin/
+	mv ../dist/battery.tmp ../dist/battery
+
+../dist/battery.tar: ../dist/battery
+	cd ../dist/battery && pax -w -x ustar . >../battery.tar.tmp
+	mv ../dist/battery.tar.tmp ../dist/battery.tar
+
+../dist/battery.tar.gz: ../dist/battery.tar
+	gzip -c <../dist/battery.tar >../dist/battery.tar.gz.tmp
+	mv ../dist/battery.tar.gz.tmp ../dist/battery.tar.gz
+	
+.PHONY: all clean sane

battery/battery

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+subprogram="$(command -v "$0")"
+if ! nonzero "$subprogram" && ! test -e "$0"; then
+	printf "%s: can't find myself!\n" "$0"
+	exit 70 # sysexits(3) EX_SOFTWARE
+else
+	subprogram="$0"
+fi
+
+# battery -> battery.linux battery.netbsd etc
+subprogram="$0"."$(uname | lowercase)"
+
+if ! command -v "$subprogram" >/dev/null 2>&1 && ! test -e "$subprogram"; then
+	printf "%s: unsupported system\n" "$(uname)" 1>&2
+	exit 70 # sysexits(3) EX_SOFTWARE
+fi
+
+"$subprogram" || exit 70 # sysexits(3) EX_SOFTWARE

battery/battery.linux

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# this is a dirty hack.
+# acpi | awk '{print $4}' will print the battery percentage,
+# and s/,$// strips the trailing comma.
+acpi | awk '{print $4}' | sed 's/,$//'

battery/battery.netbsd

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+envstat -s acpibat0:charge \
+	| sed 1,2d \
+	| cut -d ':' -f 2 \
+	| awk '{print $1}' \
+	| cut -d '.' -f 1

battery/batterymonitor

@@ -0,0 +1,33 @@
+#!/bin/sh
+
+POLLING_FREQUENCY=1
+
+# ISO 8601
+alias date="date '+%Y-%m-%dT%T'"
+
+emit() {
+	printf "[%s] " "$(date)"
+	echo "$@"
+}
+
+! battery >/dev/null 2>&1 \
+	&& printf "Unable to get battery status on this system.\n" 1>&2 \
+	&& exit 1 \
+	|| true
+
+current_level=$(battery)
+previous_level=$current_level
+
+emit "$(printf "Current level: %d%%" "$current_level")"
+
+while true; do
+	current_level=$(battery)
+	if ! [ $current_level -eq $previous_level ]; then
+		[ $current_level -lt $previous_level ] \
+			&& emit "$(printf "Discharged: %d%% -> %d%%\n" $previous_level $current_level )" \
+			|| emit "$(printf "   Charged: %d%% -> %d%%\n" $previous_level $current_level )"
+		previous_level=$current_level
+	fi
+
+	sleep $POLLING_FREQUENCY
+done