ex=ftx sym=lunausd
# first we do a "fake" sell of all luna (base currency) to save the current total balance in the "lastqty" variable... 
sell q=100% disabled save
buy q=lastqty@ type=limit
# ... then we place a limit buy using the absolute quantity we just saved, effectively doubling our balance (spot "position") 

Attention

Always double check that you are using the right syntax/alert!