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.
Again on IRC, somebody asked how to remove duplicates from a file, but keeping only the last occurrence of each item. The classic awk idiom awk '!a[$0]++' prints only the first instance of every line. So if the input is, for example foo bar baz foo xxx yyy bar the "normal" output (ie using the [...]