Registering RHEL 6

Initially when you install a new RHEL 6 on your pc and try using even basic utilities like gcc, it will show errors like no package named gcc installed. Even when you do yum install gcc it won't work and will throw errors like:

# sudo yum install gcc 
Updating Red Hat repositories.
Setting up Install Process
Error: Nothing to do

No package gcc available.

If you try

#sudo yum grouplist

Loaded plugins: product-id, subscription-manager Updating Red Hat repositories. No group data available Error: for configured repositories
If you try
#sudo yum repolist
Loaded plugins: product-id, subscription-manager
Updating Red Hat repositories.
repolist: 0

All these problems are mostly because your newly installed RHEL is not registered. You can confirm this by giving following command.
# yum repolist all

If the system is not registered it will give ouptut status as disabled. Now you can register your system with following command and then enter the required details.
# sudo rhn_register

After it has successfully registered, give following command.
#yum update