The problem is likely with the computer, not the program. This is the first program I've tried to run on it since I replaced the hard drive a few months ago - as everything on the old drive was lost I was effectively starting from scratch. I don't think I need to install perl - I've never had to do that before. The USSv4a.pl file is in the Rosie directory, as is the settings.txt file it calls. I could create a 'Hello World' perl file to test that perl is working but my perl book is at my office; maybe I can find one online ('Hello World' file, not perl book).
Yes I can (it's just one line), but now I discover that TextEdit will only save files as rtf, html, word and wordxml! Wtf? Guess I'd better install Komodo Edit. OK, I remember that finding a Komodo Edit download site took a bit of looking (Komodo IDE was easy to find but costs a bundle), but Google found a site for downloading Komodo Edit. Unfortunately what this has given me has a '.msi' suffix, and my Mac doesn't know what to do with it. On looking more carefully at the source site, I see that it says something about bittorrent, which I don't know how to use. Back to Google - OK, a site offering a Mac version, which is coming in (very slowly) as '.dmg'.
OK, got Komodo Edit, in Applications folder, opening for first time involves 'pre-loading' various bells and whistles, Mac gets VERY HOT (Fan Control maxed out).
OK, I created the Hello World file, and it ran fine. Hmm, maybe there IS something wrong with the USSv4a.pl program. Well, now I have Komodo Edit so I can take a look at it. It looks fine, so I created a 'test' version with Hello World print lines at various places. None of them gets printed. I see that the undergrad has inserted a 'die' reporting step if the program can't open its settings file, so I think that's not the problem. Instead Terminal acts as if the USSv4a.pl file and the new USSv4atest.pl file don't exist.
Back to the original USSv4a.pl file; now Komodo is claiming that every line fails to end with the expected "LF" end-of-line marker, but when I have it show the markers they all look fine. The USSv4atest.pl file markers look exactly the same, and Komodo has no problem with them.
Time to quit working on this for now. Maybe I'll send an email to the undergrad, or maybe I'll just wait till I get to my office (maybe not till tomorrow) and try to run it there.