Regex in hive

in your databases have many fields but one filed have data something like this: a1955ce0b318391b contain only a-z0-9 but some errors occurs while collect and store to database somehow that field contains null values or some dummy charracter how to filter which entry errors use this regex:
> select idvisitor from log where day = '2013-11-29' and idvisitor not rlike '^[a-z0-9]{16}$';
what does it means in hive?
rlike mean: regular expression like to use regex in hive query.
^ : from start of line
[a-z0-9] only contain a-z or 0-9 without order.
{16} contains exact 16 characters.
$ end of line.
It save my day.
:)

Using regular expression format your text

find pattern in text (this kind of regular expression can be use with text editor like notepad++ or sublime):
to find any pattern you want replace text with pattern  :     ^.*pattern.*$
to find any blank line ^.\n
meaning of each character maybe in next post.
or can use sed command in linux box for search pattern:
sed '/^.*object.*$/d' ./filename.txt : this command will print all line NOT include "object" (without quote) of filename.txt in the terminal. 
or say: sed '/^.*object.*$/d' ./filename.txt >> newformatedtext.txt 
:)