The example baraction.sh script shipped in Scrotwm's release relies on the
behaviour of the OpenBSD versions of iostat, apm and typeset, as well as
some non-POSIX Bash features.

This patch modifies the script so it is possible to run it unmodified on
a Debian system, provided the called commands are available. It uses acpi
instead of apm, which is the best choice for virtually all modern systems.
Index: scrotwm/baraction.sh
===================================================================
--- scrotwm.orig/baraction.sh	2009-05-31 19:17:46.000000000 +0200
+++ scrotwm/baraction.sh	2009-05-31 19:18:05.000000000 +0200
@@ -1,5 +1,8 @@
 #!/bin/sh
 
+ACPI=/usr/bin/acpi
+IOSTAT=/usr/bin/iostat
+
 print_date() {
 	# The date is printed to the status bar by default.
 	# To print the date through this script, set clock_enabled to 0
@@ -10,81 +13,55 @@
 }
 
 _print_cpu() {
-	typeset -R4 _1=${1} _2=${2} _3=${3} _4=${4} _5=${5}
-	echo -n "CPU:${_1}% User${_2}% Nice${_3}% Sys${_4}% Int${_5}% Idle     "
+	echo -n "CPU: ${1}% User ${2}% Nice ${3}% Sys ${6}% Idle     "
 }
 
 print_cpu() {
 	OUT=""
-	# iostat prints each column justified to 3 chars, so if one counter
-	# is 100, it jams up agains the preceeding one. sort this out.
+	# Remove the decimal part from all the percentages
 	while [ "${1}x" != "x" ]; do
-		if [ ${1} -gt 99 ]; then
-			OUT="$OUT ${1%100} 100"
-		else
-			OUT="$OUT ${1}"
-		fi
-		shift;
+		OUT="$OUT `echo $1 | cut -d '.' -f 1`"
+		shift
 	done
 	_print_cpu $OUT
 }
 
-print_apm() {
-	BAT_STATUS=$1
-	BAT_LEVEL=$2
-	AC_STATUS=$3
-
-	if [ $AC_STATUS -ne 255 -o $BAT_STATUS -lt 4 ]; then
-		if [ $AC_STATUS -eq 0 ]; then
-			echo -n "on battery (${BAT_LEVEL}%)"
-		else
-			case $AC_STATUS in
-			1)
-				AC_STRING="on AC: "
-				;;
-			2)
-				AC_STRING="on backup AC: "
-				;;
-			*)
-				AC_STRING=""
-				;;
-			esac;
-			case $BAT_STATUS in
-			4)
-				BAT_STRING="(no battery)"
-				;;
-			[0-3])
-		 		BAT_STRING="(battery ${BAT_LEVEL}%)"
-				;;
-			*)
-				BAT_STRING="(battery unknown)"
-				;;
-			esac;
-		
-			FULL="${AC_STRING}${BAT_STRING}"
-			if [ "$FULL" != "" ]; then
-				echo -n "$FULL"
-			fi
-		fi
-	fi
+print_acpi() {
+	BAT_STATUS=$3
+	BAT_LEVEL=`echo $4 | tr -d ','`
+
+	case $BAT_STATUS in
+	"Charging,")
+		FULL="on AC: (battery ${BAT_LEVEL})"
+		;;
+	"Discharging,")
+		FULL="on battery (${BAT_LEVEL})"
+		;;
+	"")
+		FULL="on AC (no battery)"
+		;;
+	*)
+		FULL="(battery unknown)"
+		;;
+	esac;
+
+	echo -n "$FULL"
 }
 
-while :; do
-	# instead of sleeping, use iostat as the update timer.
-	# cache the output of apm(8), no need to call that every second.
-	/usr/sbin/iostat -C -c 3600 |&	# wish infinity was an option
-	APM_DATA=""
-	I=0
-	while read -p; do
-		if [ $(( ${I} % 1 )) -eq 0 ]; then
-			APM_DATA=`/usr/sbin/apm -alb`
-		fi
-		if [ $I -gt 2 ]; then
-			# print_date
-			print_cpu $REPLY
-			print_apm $APM_DATA
-			echo ""
-		fi
-		I=$(( ${I} + 1 ));
-	done
+# instead of sleeping, use iostat as the update timer.
+# cache the output of acpi(1), no need to call that every second.
+ACPI_DATA=""
+I=0
+$IOSTAT -c 3 2>&1 |
+while read IOSTAT_DATA; do
+	if [ $(( ${I} % 10 )) -eq 0 ]; then
+		ACPI_DATA=`$ACPI -b`
+	fi
+	if [ $(( ${I} % 3 )) -eq 0 ] && [ $I -gt 2 ]; then
+		# print_date
+		print_cpu $IOSTAT_DATA
+		print_acpi $ACPI_DATA
+		echo ""
+	fi
+	I=$(( ${I} + 1 ));
 done