1./opt
This directory is reserved for all the software and add-on packages that are not part of the default installation. For example, StarOffice, Kylix, Netscape Communicator and WordPerfect packages are normally found here. To comply with the FSSTND, all third party applications should be installed in this directory. Any package to be installed here must locate its static files (ie. extra fonts, clipart, database files) must locate its static files in a separate /opt/'package' or /opt/'provider' directory tree (similar to the way in which Windows will install new software to its own directory tree C:WindowsProgam Files"Program Name"), where 'package' is a name that describes the software package and 'provider' is the provider's LANANA registered name.
此目录保留所有的软件和附加包，不属于默认安装的一部分。例如，StarOffice，Kylix，Netscape Communicator和WordPerfect软件包通常是在这里找到。遵守版，所有的第三方应用程序应该安装在这个目录。任 何包将安装在这里必须找到它的静态文件（如额外的字体，剪贴画，数据库文件）必须找到它的静态文件保存在一个单独的/选择/ 'package或/选择/ 'provider目录树（类似于用Windows将安装新的软件到自己的目录树C： Windows 程序文件“程序名”），在“包”是一个名字，描述了软件包的供应商的供应商的lanana注册名称。
这里主要存放那些可选的程序，比如：安装firefox，装到/opt目录，这样，当你想删掉firefox的时候，你就可 以直接删除它，而不影响系统其他任何设置。安装到/opt目录下的程序，它所有的数据、库文件等等都是放在同个目录下面。
2./usr/local
This is where most manually installed (ie. outside of your package manager) software goes. It has the same structure as /usr. It is a good idea to leave /usr to your package manager and put any custom scripts and things into /usr/local, since nothing important normally lives in /usr/local.
这里主要存放那些手动安装的软件，即 不是通包管理工具或apt-get安装的软件。