#!/bin/bash
#edit by www.jbxue.com
trap "_reload $1" 1
_f1(){
  echo $$
  while((1))
  do
    date
    sleep 0.5
  done
}

_f2(){
  echo $$
  while((1))
  do
    uptime
    sleep 0.5
  done
}

_reload(){
   [ $1 -eq 2 ]&&echo $$
}

case $1 in
   1)
     _f1;;
   2)
     _f2;;
esac