AsyncExecCommand Property MSBuild Extension Pack Help 4.0.12.0
Gets or sets the command(s) to run. These can be system commands, such as attrib, or an executable, such as program.exe, runprogram.bat, or setup.msi. This parameter can contain multiple lines of commands (each command on a new-line). Alternatively, you can place multiple commands in a batch file and run it using this parameter.

Namespace: MSBuild.ExtensionPack.Framework
Assembly: MSBuild.ExtensionPack (in MSBuild.ExtensionPack.dll) Version: 4.0.0.0
See Also

Reference