プロセス名を元に、そのアプリのウィンドウを操作する ref: http://qiita.com/items/198feae9488edc25c5d9

Sample_func_process.ahk

; Sample: Send key stroke to the window from process name.

NotFound = 0

ProgramFileName = cmd.exe

Process, Exist, %ProgramFileName%
PID = %ErrorLevel%

If(PID == NotFound)
{
  MsgBox, Process"%ProgramFileName%" not found.
  ExitApp
}

; activate command prompt.
WinActivate, ahk_pid %PID%
WinWaitActive, ahk_pid %PID%
sleep, 500
; send key stroke to command prompt
ControlSend,  , echo message, ahk_pid %PID%

Sample_Send_AltTab.ahk

Send, {ALT DOWN}{TAB}