If you mean in a normal text terminal, then look into the proper VT-100 escape codes. In that table "^[" is used as a symbolic representation of the escape character, chr(27) — in Perl you can use "\e".

So I think you want

print "\e[5m";
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after which you can print your text. Disable it again with

print "\e[0m";
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I must say: I've tried it, and it doesn't blink. I think the resulting behaviour is very much dependent on your terminal. Instead, I see dark red on black. At least it stands out.