waits for a file to have read group permissions before running a certain command

wait-for-chmod.sh

#!/bin/bash
# Copyright @st3b1t 2023
#
# usage: ./wait-for-chmod.sh /path/to/file/to/check <next-command>
#
# example, check bitcoin cookie file is readable by group:
#   ./wait-for-chmod.sh /home/bitcoin/.bitcoin/.cookie <next-command>
#
set -e

perm='-rw-r-----'

file="$1"
shift
cmd="$@"

#set -x
until [[ `stat -c %A $file | cut -c5 ` = 'r' ]]; do
  >&2 echo "Group permissions is not readable..."
  echo `stat -c %A $file`
  sleep 1
done

>&2 echo "Group permissions is readable"

exec $cmd