Yesterday I made a change on a Cisco Switch and forgot to do a copy start run

Wanted to know what the differences between the running-config and startup-config are:

apf-ma-core-sw01#show archive config differences
Contextual Config Diffs:
interface GigabitEthernet0/2
 +switchport access vlan 2

The startup-config contains the +switchport access vlan 2 line. I have removed it from the running-config

Once I was happy that I hadn't made any weird changes that would cause a problem at the next power-cycle I did a copy run start.