sway-lsof-mon

#!/bin/bash
declare sway_lsof_f="/dev/null"
declare -i sleep_duration=1
declare -i sway_pid

sway_pid="$(pgrep -x sway)" || {
  echo "sway process not found" >&2
  return 1
}

sway_ps() {
  ps --no-heading -ocommand "$sway_pid"
}

sway_cmd="$(sway_ps)"

sway_lsof() {
  # ensure sway is still running
  if [[ "$sway_cmd" != "$(sway_ps)" ]]; then
    echo "sway command '$sway_cmd' disappeared" >&2
    return 1
  fi

  local f l
  f="/tmp/sway_lsof-$(date +%s)"
  l="$(lsof -F 0tfn -p "$sway_pid" | tr '\0' '\t' | column -tN5 | sort -k 2)"

  if [[ -e $sway_lsof_f ]]; then
    diff "$sway_lsof_f" <(cat <<< "$l") && return 0
  fi

  echo "$l" > "$f"
  echo "total open files: $(wc -l "$f")" >&2

  if [[ -f "$sway_lsof_f" ]]; then
    rm "$sway_lsof_f"
  fi
  sway_lsof_f="$f"
}

trap 'rm $sway_lsof_f 2>/dev/null' EXIT

while sway_lsof; do
  sleep $sleep_duration
done