Re: Making diff(1) of linux kernels faster

[Nick Craig-Wood]

Horst von Brand wrote:
> willy tarreau <[e-mail]> said:
> > Be very careful not to modify a multi-linked file, or
> > it will be damaged in all trees and won't be seen by
> > diff. your editor must unlink before saving.
> 
> Most don't. ed(1), vi(1) and emacs(1) are careful tro write to the very
> same file. jed(1) is the only outlier I'm aware of...

emacs does mv file file~ before saving file so the edited file will
not be linked byt the backup file will be.  You can stop it doing this
by setting backup-by-copying-when-linked.

$ echo "Test1" >> test1
$ ln test1 test2
$ emacs test2 # modify and save the file
$ ls -i test*
2491498 test1  2491500 test2  2491498 test2~

However as Horst von Brand noted if you try this with (standard) vi
you will edit the linked file which is the same behaviour as if you
set backup-by-copying-when-linked in emacs.

-- 
Nick Craig-Wood
[e-mail]