Because you are using =~ 
until(!defined($_ = <STDIN>) and /exit|quit|(^\s*$)/i) {
}

[download]
or
while(<STDIN>){
    last if /exit|quit|(^\s*$)/i;
}

[download]

In reply to Re: $_ unitialized by Anonymous Monk
in thread $_ unitialized by alexx1523

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