 <p>The highest available version of GCC in the 12.04 repositories is 4.6. You can use the package manager to install a newer version, but you will have to add a PPA. <a href="http://ubuntuhandbook.org/index.php/2013/08/install-gcc-4-8-via-ppa-in-ubuntu-12-04-13-04/" rel="nofollow">This</a> link should help, although it is for a slightly older version of GCC (but can be used for the newest version).</p> <p>As a commenter pointed out, if your own built version of GCC was compiled with the <code>--prefix</code> parameter, the entire installation should be in that directory under <code>/usr/local</code> or wherever you installed it, and can be removed.</p>