Most probably due to very limited experience in programming and in working with gretl I'm currently stuck with the following issue: I have a data file with time series of monthly returns of AEX stocks from 1973 to 2007. By using a script (attached and probably not the most elegant) I'm trying to accomplish 2 things: 1. Count the number of "valid" stocks, that is stocks which have 12 months of returns data prior to t=0. 2. Only the stocks which fulfil the above mentioned criteria should be copied to a new data file (appended). Can anyone please explain to me how to accomplish #2 because just with "store" instruction the data gets overwritten.