Thank you, Pat.
That solves the problem! The COMMAND$ keyword is new to me – and I see it is new-ish to HTBasic.
(I came to HT Basic from HP Basic running on the Basic Language Processor card – a co-processor which plugged into ISA slot on the earliest IBM PCs!)
Interestingly, double-clicking the .prg file works fine to launch my program on HTB 10.13 but not on HTB 10.03. I think this is a known issue but I am not sure which versions will launch a progran from a double click on the .prg file. I haven’t yet found anything in the HTB version history which documents which versions work and which do not when you double click the .prg.
Thank you again,
Peter
