pid-file.sh <pid-file> <appear|disappear> [wait sec]

pid-file.sh

#!/usr/bin/env bash

file=$1
to=$2
wait_seconds=$3 # optional

[[ $file == "" ]] && echo "No file given." && exit 1
[[ $wait_seconds == "" ]] && wait_seconds=10
[[ $to == "" ]] && echo "Wait for file to appear or disappear?" && exit 1

waited_seconds=0

while [[ (($to == "appear" && ! -e $file) || ($to == "disappear" && -e $file)) && $waited_seconds -lt $wait_seconds ]]; do
  printf "."
  sleep 1
  waited_seconds=$[waited_seconds + 1]
done

if [[ $waited_seconds -ge $wait_seconds ]]; then
  printf " (timeout after $waited_seconds seconds)"
fi

if [[ ($to == "appear" && ! -e $file) || ($to == "disappear" && -e $file) ]]; then
  printf " FAILED\n"
  exit 1
else
  printf " OK\n"
  exit 0
fi