As far as I can tell, those two regexes are identical: one as a plain match, and one as a substitution.

I'm guessing somebody is first testing to see if anything is found, and if it does, replace it.

Don't do that. Just plain s/// is enough, it won't do anything if nothing is found, so it's safe.

Now all you've got is needless repetition, and a source of errors if somebody does a bad job copy/pasting after the regex is updated.

Now, as far as what it's trying to match, it's hard to tell formatted like this, but it looks like somebody tried to match a string looking like "%TABLE ... %" with something (of a specific format) instead of the "...", and in that something, the string 'name="History' (plus something more) ought to be found.

Well: it is wrong. It'll most likely do a substitution on a larger string, spanning more than one such string, if the first one doesn't contain that substring. As a simple example: it'd match a string like "%TABLE% blah blah blah %TABLE name="History"(something)%" as a single match. I don't think that is what's intended.

Better would be to try in match the string in a first step, and in the substitution, see if it contains that substring. If it does: substitute; if it doesn't: leave the original matched string.

At the very least, you should forbid presence of a "%" character between the "%TABLE" and the "name=" parts.

In reply to Re: Regular expression Problem by bart
in thread Regular expression Problem by archimca

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