#!/bin/sh

if [ "$#" -eq 0 ]; then
  echo >&2 "Usage: $0 <keyid> [ <depth> ]"
  exit 1
fi

keys="$1"
depth="${2:-1}"

while [ "$depth" -gt 0 ]; do

  keys=$(gpg --with-colons --fast-list-mode --list-sigs $keys | awk -F ':' '$1 ~ /sig|rev/ {print $5}' | sort -u)
  gpg --recv-keys $keys

  depth=$((depth - 1))
done