Sometimes you have to execute a binary to see if it exists. eg, if you're checking to see if you have GNU cp, you can't just see if there's a file called cp, you need to examine the binary. The easiest way of examining the binary is to execute it.
See, eg, App::Rsnapshot::CheckGNUcp
(please don't use App::Rsnapshot, it's an experimental and as-yet-incomplete rewrite of rsnapshot)
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maybe safer to try binary --help
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[d/l] |
Yes, but even so, you still have to run the thing. In the case of that particular module, the feature of GNU cp I care about is the -l flag, so that's what I test. If you look in the tests for the module, you'll see that they use --help, so that I'm comparing data from two sources.
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