What is a command link and an output link in Salesforce ?

Apex:commandLink>:This tag creates a link that helps to execute an action defined in a controller.  Normally action can be executed using buttons but in situations where you need links to be placed on your page we can use this tag. Similar to the command button tag action method, this links also transfers control to a different and then either refreshes the current page, or navigates to a different page based on the PageReference variable that is returned by the action. An < apex:commandLink > component must always be a child of an < apex:form > component.

To add query string parameters to an < apex:commandLink >, specify them in the associated action method attribute.

Syntax:
<apex:commandLink action="{!save}" value="Save" id="theCommandLink"/>

Apex:outputLink – The <h:outputLink> renders a fullworthy HTML <a> element with the proper URL in the href attribute which fires a bookmarkable GET request. It cannot directly invoke a managed bean action method.

<apex:outputlink value=”https://www.google.co.in”> Google </apex:outputlink>

<apex:outputlink value=”/{!r.Id}”> {!r.Name} </apex:outputlink>

Thanks.