How to search and get error log or info log

[inventor2014]

if want to get error log only or info log only, how to search and get with JSON

i am not familiar with
var mySearch = "search * | head 5";

do not know whether data are in ascending or descending in date

is head 5 meaning that the latest 5 records

[alacercogitatus]

Review this.

http://docs.splunk.com/Documentation/Splunk/6.0/Search/Usethesearchcommand

But to answer more completely, events are returned in latest to earliest (most recent to farthest back) order by default, and head 5 indicates you only want the first 5 events returned.

[Ayn]

Sounds like you really need to take the basic Splunk tutorial.