Re: [PATCH] sed: add --error-if-unmodified to error out if input was not mutated

[Florian Schmaus]

As I was pointed out yesterday by my fellow Gentoo developers, this 
patch barely scratches the surface of what could constitute sed mutating 
the input and misses a lot of cases. So please consider this an 
idealistic but naive approach. :)

I was already aware that my patch only handles the 's' command, but 
people came up with very interesting combinations of commands and sed 
command line flags that would mutate (or not) the input.

I think what is left is me asking the developers of sed if adding such a 
functionality in a reliable, efficient, and maintainable way can even be 
considered possible?

- Flow