Answer by Aki for Lua - Nested if statements

What you described is logical disjunction or so called OR. See Wikipedia article and Programming in Lua 3.3.

a = alarm.get("GF91908920-49330")if regexp(a.message, "/CCF_[0-9]{6}_[0-9]{2}.csv/") or   regexp(a.message, "/Issues_[0-9]{4}-[0-9]{2}-[0-9]{2}.csv/") or   regexp(a.message, "/POL_Operator_[0-9]{6}_[0-9]{2}.csv/") then       -- do somethingelse   print("We need an alarm - ", a.message)end

Assuming you actually have regexp implemented then that's it. If no, in Lua there are patterns available. You can read about them in Programming in Lua 20.2.

I highly recommend learning basics and doing at least minimal amount of research before you ask a question. Programming in Lua is available online and it is a great way to start with Lua.