A few more ways, I think the last would be my choice

print "Match1\n" if "aa1" =~ /^(a)\1()1$/;;
Match1

print "Match1\n" if "aa1" =~ /^(a)\1(?:)1$/;;
Match1

print "Match1\n" if "aa1" =~ /^(a)\1(?:1)$/;;
Match1

print "Match1\n" if "aa1" =~ /^(a)\1+1$/;;
Match1

print "Match1\n" if "aa1" =~ /^(a)\1{1}1$/;;
Match1

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In reply to Re: How we can separate a backref from a digit? by BrowserUk
in thread How we can separate a backref from a digit? by Serge314

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