bug#12366: [gnu-prog-discuss] Writing unwritable files

[Jim Meyering]

Paolo Bonzini wrote:
> [For bug-coreutils: the context here is that sed -i, just like perl -i,
> breaks hard links and thus destroys the content of files with 0400
> permission].

Did I misunderstand how "destroy" is used above?

    $ echo important > k
    $ chmod a-w k
    $ sed -i s/./X/ k
    $ cat k
    XXXXXXXXX
    $ ls -og k
    -r--------. 1 10 Sep  6 15:23 k