wget is similar to Thunder, is a download tool to download the installation package
yum : it is redhat, centos under the system software installation download the installation package and automatically install dependencies and some
Based on RPM packages can be automatically downloaded from the server specified RPM package and installed automatically handle dependencies and install all dependent packages.
RPM : software management redhat software format rpm r = redhat p = package m = management for installing software uninstall .rpm
GET-APT : a case of ubuntu software installation , which is based debain.