Who could explain error backtrace of erlang?

Question

1. Is there a good method to print pretty error trace in shell?
2. How to understand the error trace?

Thanks!

error 2012-05-30 15:53:49 <0.132.0> {supervisor_report,
[{supervisor,{local,ems_media_sup}},
        {errorContext,child_terminated},
        {reason,{undef,[{erlang,raise,[{timeout,
{rtmp,<<"http://video.zengee.com/clip.mp4">>}}],""},{rtmp_lib,play,1,[{file,"src/rtmp_lib.erl"},
    {line,159}]},    {ems_media,handle_info,2,
    [{file,"src/media/ems_media.erl"},
    {line,837}]},{gen_server_ems,handle_msg,5,[{file,"src/core/gen_server_ems.erl"},
    {line,580}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,227}]}]}},
    {offender,[{pid,<0.718.0>},{name,ems_media},{mfargs,{ems_media,start_link,
[rtmp_media,[{host,default},{name,<<"videojs">>},
    {type,rtmp},{url,"http://video.zengee.com/clip.mp4"}]]}},{restart_type,permanent},{shutdown,3000},{child_type,worker}]}]}

Answer 1

See reason tag. In your example:

 {reason,{undef,[{erlang,raise,[{timeout,...

Erlang undef - The function cannot be found when evaluating a function call.