parent.sh

{
     leaf=$$
     ps -eo pid,ppid,command | awk -v leaf="$leaf" \
        '{parent[$1]=$2;command[$1]=$3;}
     function print_ancestry(pid)
     {
         print pid " (" command[pid] ") child of " parent[pid];
         if(pid!=1) print_ancestry(parent[pid])
     };
     END{\
         print_ancestry(leaf)
     }'
}