Issues progressively more severe kill signals to one or more PIDs

safe-kill.sh

#!/bin/bash

test -z "$1" && exit 1
declare -a _PGREP; _PGREP+=('pgrep')
test ${#1} > 15 && _PGREP+=('--full')
_PGREP+=('--ignore-ancestors' "$1")
mapfile -t _PIDS < <("${_PGREP[@]}")
test ${#_PIDS[@]} = 0 && exit 1

_SIGNALS=(15 1 3 6 9)
for _SIGNAL in "${_SIGNALS[@]}"; do
  test $_SIGNAL != 15 && \
    mapfile -t _PIDS < <("${_PGREP[@]}")

  for _PID in "${_PIDS[@]}"; do
    kill -$_SIGNAL $_PID >/dev/null 2>&1
  done

  sleep 0.25
  mapfile -t _PIDS < <("${_PGREP[@]}")
  test ${#_PIDS[@]} = 0 && break
  sleep 4.75
done