Here’s how to get the selection from the script history. This is how the Repeat command works.

def GetScriptHistoryView():
	oLayout = Application.Desktop.ActiveLayout

	# See if the script history is a view of it's own
	oViews = oLayout.Views.Filter( "Script History" )
	if oViews.Count == 0:
		oViews = oLayout.Views.Filter( "Script Editor" )

	return oViews(0)

oLog = GetScriptHistoryView()
text = oLog.GetAttributeValue( "historyline" ) if oLog else "<Nothing>"
print text