MSTSC

Connect and login to a remote machine using the Remote Desktop Protocol (RDP) also known as Terminal Server Connection (TSC.)

Syntax
      MSTSC option
      MSTSC /Edit "ConnectionFile"
      MSTSC /migrate

Options
   ConnectionFile     The name of an RDP file for connection

   /v:<server[:port]> The remote computer to connect to

   /console       Connect to the console of a server (NT/XP)
   /Admin         Connect to a session for administering the server(Vista/2008)

   /f             Start in Full Screen mode

   /w:width       Width of the RDP screen
   /h:height      Height of the RDP screen

   /span          Match the Remote Desktop width and height with the local virtual
                  desktop, spanning across multiple monitors if necessary.(Vista/2008)

   /public        Run Remote Desktop in public mode. (Vista/2008)
                  In public mode, passwords and bitmaps are not cached.

   /edit          Open the RDP file for editing.
   /migrate       Convert a legacy Client connection file into an .RDP file

The /console option only works when connecting to an Windows XP Professional or Windows Server 2003 computer.

To connect to a remote computer the user account must be a member of the local group 'Remote Desktop users' on the remote server (either directly or inherited via a global group) in addition the user account needs the privilege SeRemoteInteractiveLogonRight (allow logon through RDP/Terminal Services.)

When connected to a remote desktop, the key combination Ctrl-Alt-END will send Ctrl-Alt-Del to the remote client.

Examples:

MSTSC /v:MyServer /f /console
MSTSC /v:127.0.0.1 /w:1024 /h:768
MSTSC /v:MyServer /w:800 /h:600
MSTSC /edit filename.rdp

Copy and paste is supported between a remote computer and your local machine, but RDP has a 'hidden feature' of converting TABs into spaces!

“Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong” - Thomas Jefferson

Related:

Remote Desktop Connection Manager - RDP to multiple machines.
Q216783 - Keep-Alive Disconnected TS Connections
Q2726399 - Cannot change the DPI setting through an RDP session.
MAPISEND - Send email from the command line
RMTSHARE - Share a folder or printer
SHORTCUT - Create a windows shortcut
SHADOW - Monitor/View another users running RDP session.
SHUTDOWN - Shutdown the computer/Log off a user
Equivalent bash command (Linux): VNCconnect or screen