I'm implementing pstree as an assignment,

and I would like to create test tree of processes, but I'm struggling to do so.

I tried to do something like this to create tree of background processes so I can test my script later.

recursive tree of processes


        echo "mine PID is: "$$

        local -i level=$(expr $1 - 1)  # level of recursion

        if [[ $level -gt 0 ]]; then
          echo $level
          childProcess $level &           # we do binary tree
          echo "Process with  PID $! launched"
          childProcess $level &
          echo "Process with  PID $! launched"
          sleep $level
          echo "baf! "$level" pid is: "$$

# create binary tree of depth 4
for (( i = 0; i < 2; i++ )); do
    childProcess 4 &
    echo "running proces no. :"$!

But I would like to echo PID from within of process, and with this I can't.

Another not-working-solution would be this, but it creates processes in "DFS manner".

declare -i level=$1

if [[ $level -gt 0 ]]; then
  sh $0 $(expr $level - 1)  # spawn children
  sh $0 $(expr $level - 1)  # spawn children

  sleep 100;
  echo "level :"$level" process no: "$$

Can anyone tell me how to construct tree of processes which I can acces by PID, and that would be there until I delete them, e.g. by killing oldest process.

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