Regular Expression for a string

[Roy Smith]

In article <1162440285.962155.325540 at f16g2000cwb.googlegroups.com>,
 "Teja" <tejovathi.p at gmail.com> wrote:

> HI all,
> 
> I need to write a regular experssion for a string which satisfies the
> following a criteria :
> 
> 1) it should start with an alphabet

I assume you mean, "It should start with a letter"?

> 2) it can contain alphabets/digits/_ from second character
> 3) it can contain "[a-z]" or "[0-9]" at the end. but this is optional

How about:  ^[a-zA-Z][a-zA-Z0-9_]*[a-z0-9]?$

Probably many variations on that theme will also work.