Another habit you should get into is to check for success when you open a file and print the o/s error held in $! on failure.

$ perl -Mstrict -Mwarnings -E '
> open my $inFH, q{<}, q{doesNotExist}
>    or die qq{open: < doesNotExist: $!\n};'
open: < doesNotExist: No such file or directory
$
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