Please see my previous response:
If you mean simply extracting the contents of a .deb … making some changes … and repacking it.
Maybe this will help
Place the original.deb in a temporary directory somewhere, and “cd” into that directory…
Extract has to be done in 2 steps, first extract the package contents (the unpacked-dir in the folloing commands will be automagically created and can be called whatever you like), then unpack the /DEBIAN directory:
dpkg-deb -x original.deb unpacked-dir
dpkg-deb -e original.deb unpacked-dir/DEBIAN
then make any changes you want to in the unpacked-dir directory
(in this case I just edited the /DEBIAN/control file to change the dependency)
Rebuilding the custom .deb:
dpkg-deb -b unpacked-dir original-edited.deb
be aware some packages (specially large ones) may appear to stall during rebuilding … but give em time … also be aware that when repacked they may be smaller than they previously were (as in this bricscad case), I assume it just used a better compression algorithm.
Is that what you were after ?
Be aware - you can distribute this .deb, but there’s no way to get this .deb onto launchpad … as I’ve said before, launchpad only accepts properly formatted source code, it then builds the packages itself against the version of Ubuntu you specified in the “changes” file.
(this stops package maintainers from including pre-compiled malicious binaries without making the source code available for peer review)
For this reason it’s generally not a clever idea to accept .deb packages from someone you don’t know and trust … think about it, I could have easily included a keylogger in the custom bricscad .deb and it’d be given elevated privileges at install time.
(I haven’t BTW )
Launchpad PPA’s don’t stop someone packaging malicious code (a reason in itself to be careful with getting software from non official PPA’s), but they do force the author to divulge the source code.