Are you missing those files, or are they just not in your PATH? And if you have your package manager (yum, rpm, aptitude, dpkg, etc) available, you should just reinstall those programs from your repository.
If you actually deleted those binary files by mistake, then I think the problem is you have to download a file specific for your distro. For example, in Debian, I can just download the *.deb file and unpack it (or install it) using dpkg. If you lost your package manager (rpm), you might have to unpack the rpm file for the program "rpm" using some other utility like 7-zip. Then you should be able to copy it where it goes.
What distro are you using?