Re^4: Stupid mistakes I repeatedly make

[Roy Johnson]

You likely don't care how many times the replacement happened, but it's not uncommon to care about whether any replacements happened.

if (s/foo/bar/) {
  ...
}
else { 
  ...
}

(How many isn't even an issue unless you're using /g. It's just 1 or 0 — it replaced something or it didn't.)