Another feature proposal and implementation plan: --strip-prefix

[Edwin Olson]

Here's another feature I'd like to have:

Suppose you're copying a source file /a/b/c/d/e/f/g/h/myfile and you 
want it stored on some other filesystem /backup, but you want the source 
path to be truncated so that the file actually ends up as: /backup/h/myfile.

This comes up (in particular) when doing backups of windows machines via 
cygwin; you end up with a phony base directory /cygdrive/. When users go 
to see their backups, they become confused! This option would eliminate 
this problem.

I'd like to add this behavior, similar to the patch -p option.

I'm uncertain whether the syntax should be 
--strip-prefix=/a/b/c/d/e/f/g, or --strip-prefix=7. The former would 
allow us to detect situations in which we were being asked to copy files 
that did not have the expected prefix and to complain loudly (or 
silently ignore the strip prefix directive for that file?) The latter 
would be more like patch -p, but I think it's less safe. Perhaps 
multiple --strip-prefix directives should be allowed so that a single 
invocation of rsync can handle more complicated situations.

I think this can be relatively cleanly implemented in recv_files; in 
fact, the line "fnamecmp=fname;" in reciever.c seems to be exactly the 
hook required. Like my previous email, I would like to ask for advice 
and suggestions so that my implementation will be most useful!

Thanks,

-Ed