In addition to what everyone else has said, I'll note that you can also use an opening bracket, paren or curly, and will get to use the closing ones as might seem expectable: s{(^\d+[.]\s.+)}{<h1>$1</h1>}g; in which case you can also put space between the parts 
s {(^\d+[.]\s.+)}
        {<h1>$1</h1>} g;

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which can be helpful for readability in complex substitutions, and esp a series of them.

Makeshifts last the longest.

In reply to Re: s!!! vs. s/// by Aristotle
in thread s!!! vs. s/// by imlou

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