my $highlander;
BEGIN {
    open $highlander, '<', $0 or die "Couldn't open $0: $!\n";
    flock $highlander, LOCK_EX | LOCK_NB or do {
        warn "There can only be one $0\n";
        exit;
    };
}

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I am confused by there being a do { warn "XXX"; exit; } in this snippet rather than a simple die "XXX", especially seeing as how you are calling die if the open fails in the preceding statement. Would you be so kind as to explain the reasoning, please?

🦛

In reply to Re^2: Preventing multiple instances by hippo
in thread Preventing multiple instances by Bod

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