on *:TEXT:!*:*: {
  ;notice the addition of !* above it will only process if the channel message is starting with !
  if ($ulevel == 53) {
    if ($2 ISCHAN) {
      ;below script is processed only if $2 is chan so its not necessary to use $$2
      if (($1 == !msg) || ($1 == !say)) { msg $2- }
      if ($1 == !part) { part $$2 }
    }
    if ($2 !ISCHAN) {
      ;$2 is a channel what you intend to join , it is obvious you are not already on it so process for !join command should go under here
      if (($1 == !say) || ($1 == !msg)) { msg $chan $$2- }
      if ($1 == !part) { part $chan }
      if ($1 == !join) { join $$2 }
    }
  }
  else notice $nick You don't have permission to use me! Ask R2D2Warrior for permission!
}