I am trying to install yum utility on my centos 4 system that doesn't have any rpm utility or build-essentials
migrated from stackoverflow.com Mar 29 '11 at 1:32
I never did it, but should be possible:
Install the rpm rpm without rpm;-) I mean the rpm file, containing the rpm, but not with the rpm command.
RPM files contain their files in compressed format that you can unpack, see "rpm2cpio" for help. If you get rpm running again, the rest should be a piece of cake...
Harvest the binary /bin/rpm from a similar system, also get all the libraries needed by rpm using ldd /bin/rpm. tar the lot up and untar it on your system.