I added the [] chars around $version_on_disk and $version_dns to make sure no strange characters were coming on the variables. They print correctly on the terminal.
How can you detect a sound in brackets? Use Data::Dumper (plus $Data::Dumper::Useqq=1; as advised by jethro) or pipe your output to a hexdump.
Updated.

In reply to Re^3: Argument isn't numeric in numeric ge by choroba
in thread Argument isn't numeric in numeric ge by natxo

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