I have been using some kind of shorthand to bookmark and login to salesforce ,something like below format for normal login
https://login.salesforce.com/login.jsp?un=&pw=
where un and pw are username and passwords that i keep as bookmark .
For Portal also I have something as below format
https://login.salesforce.com/secur/login_portal.jsp?orgId=&portalId=&un=&pw=
where Org Id is organization Id and PortalId is my portal Id
I need same for communities that have login enabled with site.com or community builder for bookmark.