How to update the customer using Impex

Hi

I'm new to the hybris and learning the concepts of it. I would like to update the customer using impex script. I tried with below one

 UPDATE Customer;code[unique=true];eflyer;
 uday.madigatla@gmail.com;true;

When i validated the script in HAC, it says..

 ERROR [hybrisHTTP1] [DefaultImpexFacade] ImpEx script validation has failed: unknown attribute 'code
 ' in header 'UPDATE Customer'

So removed the 'code' and replaced with customerid. It validated correctly, but when i executed it, it throws me an error saying that...

 ERROR [hybrisHTTP8] (00000RS1) [Importer] line 2 at main script: Exception 'unknown type 'uday.madig
 atla@gmail.com' in line ValueLine[,line 2 at main script,uday.madigatla@gmail.com,HeaderDescriptor[l
 ine 1 at main script, update, Customer, {}, [customerid, eflyer] ],{1=ValueEntry('false'=null,unreso
 lved=null,ignore=false), 2=ValueEntry(''=null,unresolved=null,ignore=false)}] - cannot import' in ha
 ndling exception: unknown type 'uday.madigatla@gmail.com' in line ValueLine[,line 2 at main script,u
 day.madigatla@gmail.com,HeaderDescriptor[line 1 at main script, update, Customer, {}, [customerid, e
 flyer] ],{1=ValueEntry('false'=null,unresolved=null,ignore=false), 2=ValueEntry(''=null,unresolved=n
 ull,ignore=false)}] - cannot import

Can you please help me here to update the customer info using impex. Sample impex would help me.