As far as the system "failures" are concerned, the problem is that you cannot use or die...; to test these calls for failure. For a better explanation than I can give see sauoq's explanation at Re: Re: vanishing system call. (Notice also that he was replying to my bad use of this 'meme':)

As for the `backticks`, in essence, if the `cmd` returns no output, then the die will be triggered, but it doesn't mean that the cmd didn't execute, only that it didn't produce any output.

As for the open case working from the command line but not under the auspices of AT, the problem is probably that when it runs under the scheduler, it runs under a different account to when you are running it from the command line and that account doesn't have permission to access the file? It's a guess, but it's a problem that has come up here before.

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller

In reply to Re: When is a logical or not logical by BrowserUk
in thread When is a logical or not logical by rah

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