$User

A global merge field type to use when referencing information about the current user. User merge fields can reference information about the user such as alias, title, and ID. Most of the fields available on the User standard object are also available on $User.

Usage

Use dot notation to access the current user’s information. For example:

1{!IF (CONTAINS($User.Alias, Smith) True, False)}

Example

The following example displays the current user’s company name, as well as the status of the current user (which returns a Boolean value).

1<apex:page>
2  <h1>Congratulations</h1>
3   This is your new Apex Page
4   <p>The current company name for this 
5      user is: {!$User.CompanyName}</p>
6   <p>Is the user active?  
7      {!$User.isActive}</p>
8</apex:page>

Visualforce Developer Guide

$User

Usage

Example