Exception异常类中的backtrace的用法，求实例

$ cat x.rb
def do_division_by_zero
5 / 0
end
#begin
do_division_by_zero
#rescue => exception
# puts exception.backtrace
# raise exception # always reraise
#end
$ ruby x.rb
x.rb:2:in `/': divided by 0 (ZeroDivisionError)
from x.rb:2:in `do_division_by_zero'
from x.rb:5:in `<main>'
将#拿掉：
$ ruby x.rb
x.rb:2:in `/'
x.rb:2:in `do_division_by_zero'
x.rb:5:in `<main>'
x.rb:2:in `/': divided by 0 (ZeroDivisionError)
from x.rb:2:in `do_division_by_zero'
from x.rb:5:in `<main>'