On 05/07/2010 09:31 AM, Peng Yu wrote: > On Fri, May 7, 2010 at 10:16 AM, Eric Blake <ebl...@redhat.com> wrote: >> On 05/07/2010 09:02 AM, Peng Yu wrote: >>> Suppose I need to modify one primary file slightly to do something a >>> little bit different. But I still need to do the original job, >>> therefore I need to keep it the original M files. I can copy the whole >>> directory and then modify one file in the newly copied N files. But >>> I'll lose track of which file has been changed later on, which is >>> important to me. >> >> Consider using a version control system. Track the contents of your >> directory under your favorite VCS, like git, and then you can use >> version control commands to generate the delta for both primary and >> secondary files across any state that you committed. > > I can't use version control for > 1. I need to frequently change file names. > 2. Both primary and secondary files could be of hundred of MB or even GB.
git handles both of those situations, without too much hassle. >> But overloading bash's > and >> operators is not possible. > > Is it because the underlying library that used in bash doesn't support > the semantic of symbolic link that I propose? Or it is because of the > OS? > > Is it possible to modify source code of bash to change the semantics > of symbolic link. Yes, it's possible to modify the source of bash to change how bash treats symlinks when using the > operator. But I would advise against it, as your fork of bash would no longer comply with POSIX, and would probably break a lot more than it fixes. Rather, if you insist on modifying bash, consider adding a new operator (maybe spelled '>;', similar to the noclobber override spelling of '>|'), so that your use of the new operator is explicit that you know what you are doing in your scripts (if the operand of the new operator is a symlink, break the symlink and create a file in its place instead of operating on the target of the symlink). -- Eric Blake ebl...@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature
