This is asked very often, and the solution isn't always obvious (if at all).
Some ways to "pull out" strings from files
Problem statement: replace every Nth occurrence of a pattern. For bonus points, provide context to the match. For this article, we're going to use this example (mostly nonsensical, but that illustrates the concept): 1foo1 bar foo 2foo3 abc def foo foo foo 1foo4 foo foo 3foo9 4foo7 zzz 7foo7 3foo3 And we want, among all […]
An added twist to the usual search/replace problems.
One of the most FAQ of all times.