Linux ACPI debugger

acpidbg.sh

#!/bin/bash
set -e
path=/sys/kernel/debug/acpi/acpidbg
history -r ~/.acpidbg_history 2> /dev/null || true
if ! [ -r "$path" -a -w "$path" ]
then
	echo >&2 "acpidbg: not enough privileges"
	exit 1
fi
cat "$path" & out_pid=$!
terminate() {
	exit_code=$?
	echo "Exit" > "$path" || true
	on_exit || true
	exit $exit_code
}
on_exit() {
	wait $out_pid || true
	history -a ~/.acpidbg_history || true
}
trap terminate INT TERM
while sleep .05 && kill -0 $out_pid 2> /dev/null
do
	if echo -ne '\r' && read -p '- ' -er REPLY
	then
		if [ -n "$REPLY" ]
		then
			history -s "$REPLY" || true
			echo "$REPLY" > "$path" || break
		fi
	else
		terminate
	fi
done
on_exit