#!/bin/sh -
#
#   Oliver Fromme  <olli@fromme.com>
#
#   BSD-style copyright and standard disclaimer applies.
#
#   Trace a process through its parents up till init (PID 1).
#   If no PID is specified, it starts at your shell's PID.
#

if [ $# -eq 1 ] && TRACEPID=`expr "$1" : '\([0-9][0-9]*\)$'`; then
	shift
	SKIP=0
else
	TRACEPID=$$
	SKIP=1
fi

if [ $# -ne 0 ]; then
	echo "usage:  `basename $0` [pid]" >&2
	exit 1
fi

ps -lwwp 1 | head -1
while :; do
	if ps -p $TRACEPID >/dev/null; then :; else
		echo "No such process: $TRACEPID" >&2
		exit 1
	fi
	LINE=`ps -lwwp $TRACEPID | tail -1`
	if [ "$SKIP" != 1 ]; then
		echo "$LINE"
	fi
	SKIP=0
	if [ $TRACEPID -lt 2 ]; then
		break
	fi
	TRACEPID=`echo "$LINE" | awk '{print $3 + 0}'`
done

exit 0

#--