The correct way for others who may reach this thread from google :)

until ($question1 eq "0") {
&pytaj();
    
if ($question1 eq '') {
    print "Nie wybrales zadnej opcji \n";
    print "Zamykam.... \n";
    sleep(5);
    exit();
}

elsif ($question1 eq "1") {
&backup();
}

elsif ($question1 eq "2") {
&restore();
}

elsif ($question1 eq "3") {
&testowanie();
}        

elsif ($question1 eq "4") {
&full();
}

elsif ($question1 eq "5") {
&shared();
}

elsif ($question1 eq "6") {
&archive();
}

elsif ($question1 eq "0") {
    print "Ok wiec koniec pracy. Zamykam.... \n";
    sleep(5);
    exit();
}
}
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