Imagine I have a file with foo and bar all over the place. The tables have turned and now I want all occurrences of foo to be bar and all occurrences of bar to be foo.
Reaching for a simple substitution won't work because after flipping all the occurrences of foo to bar. I will no longer be able to distinguish between the new bars and the bars that need to be flipped.
Abolish.vim enhances Vim's substitution capabilities making it easy to flip these strings in one relatively simple command.
:%S/{foo,bar}/{bar,foo}/g
Notice the uppercase S as well as the ordering of foo and bar in the before and after sequences.