When you install applications in directories that identify their versions, multiple versions can coexist at the same directory level. To identify the default version of a given application, create a generic directory name as a symbolic link pointing to the version-named directory that you want to serve as the default.
In the following example, the /usr/apps/pkgs directory contains two versions of FooTool and a generic footool name link.
$ cd /usr/apps/pkgs $ ls -ld footool* lrwxrwxrwx 1 nobody nobody 12 Jun 19 1992 /usr/apps/pkgs/footool -> footool,v1.0 drwxr-xr-x 9 nobody nobody 512 Jun 18 1992 /usr/apps/pkgs/footool,v1.0 drwxr-xr-x 9 nobody nobody 512 May 3 21:23 /usr/apps/pkgs/footool,v2.0 $
The default ...