This directory (and version of CentOS) is deprecated. For normal users, you should use /5/ and not /5.5/ in your path. Please see this FAQ concerning the CentOS release scheme: https://wiki.centos.org/FAQ/General If you know what you are doing, and absolutely want to remain at the 5.5 level, go to http://vault.centos.org/ for packages. Please keep in mind that 5.5 no longer gets any updates