#!/bin/sh -
#
#   Print the given PID, its parent PID etc. up to init's PID.
#   If no PID is specified, start with the current shell's PID.
#   Works only with BSD-style "ps" syntax.
#
#   Copyright (C) 1997-2000 Oliver Fromme  <ollI@fromme.com>
#   Use and distribute under BSD license.
#

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
        LINE=`ps -lwwp $TRACEPID | tail -1`
        case "$LINE" in
                *${TRACEPID}*)  ;;
                *)              echo "$0:  PID $TRACEPID not found." >&2
                                exit 1
                                ;;
        esac
        if [ "$SKIP" != 1 ]; then
                echo "$LINE"
        fi
        SKIP=0
        if [ $TRACEPID -lt 2 ]; then
                break
        fi
        TRACEPID=`echo "$LINE" | awk '{print $3}'`
done

#--