They are explained in perlre.

What \Q does is disable a lot of the "metacharacters" in REs until the next \E. This is often important when substituting variables in an RE because you have little control over the contents of the variable.

An alternate solution is to quote all possible meta characters with quotemeta.

In reply to Re (tilly) 3: fixstyle script in PERL COOKBOOK by tilly
in thread fixstyle script in PERL COOKBOOK by masterhenry

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