No, please don't use grep that way, unless you actually want to strip lines out of your input if they don't match the substitution pattern. Use map, instead--that's what it's for.

@footerfile = map {s/something/else/} <FILE>;
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Note that the first solution proposed using grep wouldn't have the undesired side-effects, but it's still bad coding practice--never use grep or map in void context (obfuscatory and inefficient).

And Kage, please find a better descriptive title for your question next time...

Update: or, of course, you could alter the array in place after reading it in, using

s/nothing/something/ for @footerfile;
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Update 2: of course, it would help if I told you the right syntax for map, too...

@footerfile = map {s/something/else/;$_} <FILE>;
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