What manipulations? There are probably a lot that awk can do (I resort to it for calculations and prefer sed for text). You have to be more specific about the actual problem before anyone can recommend "the optimal tool" for it.
"in Unix" ... Do you really have a platform, where you cannot use awk?
There are many, more or less complicated ways to do it. Just try not to make it too complex because although there are programs that helps detecting bugs that are made by high complexity, as checkmarx it is better to try and avoid these issues with some simpler ways.