- s chmod 600 $f # make it 600 before writing sensitive info
- echo "$domain:${pass/:/::}" | s dd of=$f >/dev/null
+ s chmod 640 $f # before writing sensitive info
+ s chown root:Debian-exim $f
+ # reference: exim4_passwd_client(5)
+ printf "%s:%s" "$domain" "$pass" | s dd of=$f 2>/dev/null