User account management, Please Help
 

Hi, I'm new on Linux, well, I want to make two user accounts on my desktop, Ubuntu distribution, Yes, i know i can make two accounts simply, But i want several features, have a look :

1 : I want to make only one password for root.
2 : I want if a user installs any program, another user would be able to use it, by default.
3 : Is it possible to make one root password, and each user can put his customize password(not root password).
4 : If any other nice suggestion you have, then please give me to make user accounts, another user is my brother so i don't have any privacy problem, I can share root password, but in any case I may need to protect my user folder only, I don't want that i will install gimp and skype twice on my computer, If anyone can help, I'll be thankful.

1 - no, root should not have a password on Ubuntu, that's NOT how the standard works
2 - so install packages properly by Apt, as per standard
3 - do not have a root password, use sudo as per standard

Basically it looks to me like you're not aware of the sudo framework. to install a package as a user tagged as an "administrator" you can use the sudo tool to perform an action as root. e.g. "sudo apt-get install gimp" will prompt you for YOUR password, NOT the root password, and then install gimp for everyone on the system.

Can you explain in detail? I can understand what are you saying, getting two accounts means, getting two administrators, so i have to make two passwords, Okay... But still i think if you can explain it, it'd be awesome

plenty of docs out there already... https://help.ubuntu.com/community/RootSudo

Ad 2) You known that if you allow normal user (non administrator) possibility to install software off the repositories and other one to use it, then this will be a security hole? Malicious user can do anything with that power. If using only trusted repositories then it would be ok, but you can not allow to uninstall software or downgrade (it can damage system). If you really need that, I think that better will be using list of packages allowed to install (and uninstall) and then specifing that on sudoers.

Ad 3) You can get this behavior by usingor "gksudo" in graphical environment. That way every user has its password which can change a normal way and administrator can use another account without knowing his password.

Ad 4) Do not share your passwords. It is not necessary. Just configure your system. Use proper permissions, config sudo, etc. For example you should deny access to your home directory for other users, because by default on Ubuntu it has "rx" permission. None of data will be protected (if not crypted) if you give other user admin rights (for example by sudo). So only you should have that (by default users belonging to "admin" and "sudo" groups have sudo access to root account).

For user account Management ..go through this link useradd/usermod/groupadd command