Running blog post of VF examples for URLFOR that aren’t so obvious. More of an aide-memoire to myself

Clone button

<!-- Note use of URL param clone='1' -->
<apex:commandButton value="Clone" 
   action="{!URLFOR($Action.Foo__c.edit, Foo__c.id, [clone='1'])}" id="clonebtn"/>

Custom Controller – Cancel button – avoid coding a custom Cancel action method

<!-- Goes to value of current page's RetURL parameter if any; if none goes to home page -->
<apex:commandButton value="Cancel" 
                    action="{!URLFOR('/' & $CurrentPage.parameters.retURL)}"/>

Fixed domain name plus merge fields

<!-- Goes to some rest resource on known domain; note use of SFDC formula expression to concatenate-->
<apex:commandButton value="Foo" 
                    action="{!URLFOR('https://www.foo.com/' & someControllerProperty)}"/>