You're not actually USING the \b, since you will match the same things without them (the \w+ will start at the earliest possible moment and stop at the last moment, both of which points will be \b boundaries).

Now assuming you want to actually match "a/c" in the case of your example, you are also changing the meaning of \w, and your new \b still isn't used, so you can just as well write:

while ($rec =~ m![\w/]+!g) { $word = $&; }
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