what are captures?

The parens in

if ('foo 123 bar' =~ /(\d+)/) {
    print("$1\n");
}
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123
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What do you mean that m//g is a bug?

for (1..2) {
   if ('ab' =~ /a/g) {
       print("match\n");
   } else {
       print("no match\n");
   }
}
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match
no match
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for (1..2) {
   if ('ab' =~ /a/) {
       print("match\n");
   } else {
       print("no match\n");
   }
}
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match
match
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