Custom command aliases and external commands can be defined to improve access to the commands and applications you use most frequently.
A command alias is an abbreviated name that can be used to start a command in AutoCAD-based and AutoCAD LT products. Command aliases are stored in a acad.pgp (or acadlt.pgp for AutoCAD LT) file, an ASCII text file. External commands can also be defined in the PGP file for AutoCAD-based products only on Windows; not supported in the AutoCAD LT product. An external command can be used to start an application located outside of the AutoCAD environment, such as Calculator or Notepad that are installed with the Windows OS.