Originally Posted by tank junior
I don't know if it's common or restricted that when you install either open source or commercial apps and you have to assign some rights to their executable so that they can access private info, provided source of app is authenticated.
No, it isn't. For applications that come from a standard repository (eg the repository of the particular distribution), the installation process itself will normal take care of any access that is required. Some larger applications (such as a web server) may require some additional configuration, but most will work 'out of the box'. The bulk of applications simply operate at the user's privilege level.
For third party applications, installation can sometimes be a little more complex, since it may not be customized for the particular distribution.
If you find that an application does not have the access that you want, there is usually a good security reason for it. So although it is relatively easy in Linux to increase the privileges of an executable, it should only be done with great caution (and rarely if ever). Even if the application is known to be trustworthy, does not mean that you want it to have system wide access, since an untrusted user might misuse the application as a means of cracking the system (this is true whatever operating system you are running).