What is super user linux

Who is superuser in linux?

On a Linux system Superuser refer to the root user, who has unlimited access to the file system with privilege to run all Linux commands. Regular Linux user can only access files owned by the user himself. same way regular users cannot execute commands that have an effect to the hole Linux system.

Who owns superuser account?

In Windows systems, the Administrator account holds superuser privileges. Each Windows computer has at least one administrator account. The Administrator account allows the user to install software, and change local configurations and settings, and more.

Is a super user in Linux?

Sudo (superuser do) is a utility for UNIX- and Linux-based systems that provides an efficient way to give specific users permission to use specific system commands at the root (most powerful) level of the system. Sudo also logs all commands and arguments.

Where is super user in Linux?

You need to use any one of the following command to log in as superuser / root user on Linux: su command – Run a command with substitute user and group ID in Linux. sudo command – Execute a command as another user on Linux.

How do I become a Linux superuser?

1. Method 1: Use ‘sudo -i’ to become root user or superuser in Linux.
2. Method 2: Use ‘sudo -s’ to become root user or superuser in Linux.
3. Method 3: Use ‘sudo su -‘ to become root user or superuser in Linux.
4. Method 4: Use ‘su — root’ to become root user or superuser in Linux.

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What is «superuser» and how do I get that privilege?

My questions are. What is a superuser? How do I get that privilege? or is there another way to configure dpkg ?

3 Answers 3

root (superuser) is the user on the system who has all permissions.

You gain superuser rights for the duration of a command by prepending sudo in front of the command you want to execute (if your user is in the sudo group).

Enter your password when prompted.

The «superuser» is user «root» on Linux systems. It’s the «god in the system», it has full privileges to do everything. All other users don’t have those rights, and only admin users have the right to use sudo to run commands as root user.

If a command needs root rights, you must run it with sudo like this:

That will ask you for your user password. Note that no characters are echoed, not even asterisks, when you type in your password.

Basically there are three different types of users in Linux (Ubuntu).

1. Root user, which is the super user / administrator / or whatever you want to call it
2. Service users, which are hidden non-login users that are used by services such as Apache web server. These users can’t login and can’t be used by you to login.
3. Normal users, which are any other users. This kind of user can be either a sudoer or a non-sudoer.

Initially logging in as the root user is disabled by default in Ubuntu. Instead you can use your normal user which has permission to run the sudo program which makes it possible to execute commands as another user, including as root.

This will raise you an error of permission denied. So you have either to be a root or use sudo :

sudo apt-get install SOME_APP 

So back to your error, you should run it with sudo as below:

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Why does superuser exist in Unix/Linux?

The only things you can do with it, in terms of «disabling» it, are: Lock the account Give root an unusable password sudo — as user root Remember that when a user with «administrative privileges» is making use of they’re running commands with elevated privileges as the user root! Limiting access via sudo Sudo has a fairly rich facility for limiting access to specific commands, groups of commands, specific users, and/or specific groups of users.

Why does superuser exist in Unix/Linux?

The existence of a superuser, in one form or another, is logically necessary. There has to be some credential that allows configuring credentials. That’s root.

Root doesn’t have to be a user account. It could be a capability, for example. Unix historically went for a simple design and used a single concept to implement both accounts and capabilities: users. Each person who uses the system gets a user account, and system services are also assigned a user account. The system service that, among other things, has control over user credentials ( /etc/passwd , and other functionality that plays the same role on modern systems), can indirectly obtain any capability. Under the Unix design, root can also directly obtain any capability (e.g. by running su , or the underlying system call), but even if it was not so, it’s difficult to prevent the credentials manager from assigning themselves any credentials¹.

Modern systems have evolved to a more fine-grained security model. For example, Unix early on added a notion of groups to allow users to share files, but groups can only be managed by root. Most modern Unix systems have access control lists that allows users to share files without root’s intervention. More and more Linux system use security mechanisms such as SELinux that limit what even root can do.

But more complex security models are a double-edged sword. More fine-grained permissions allow for greater control, and they allow more security policies to be implemented in a simple way (for example ACL for access rather than indirect access through setuid programs). But more complex security policies are harder to review (there’s so much more to review, in a more complex language), and the code to implement those policies is more complex hence has more risk of being buggy.

¹ _{This can be prevented by dual control or by cryptographic means, but that limits functionality (if there’s no way to run arbitrary code with ultimate privileges) and availability (if the system is locked down too much, this increases the risk of getting locked out).}

If you wouldn’t have a superuser, you would need to be able to execute all tasks, that now require privilege elevation, as a normal user.

That would make it even more dangerous to leave your desk unattended, because anyone who gets at your keyboard before the screensaver locks the sytem will be able to e.g. add a new user account, format the disk etc.

Removing the superuser would not remove the attack target for exploits, it would just create an easier one.

Because you should be free to do what you want with your system, I suppose the creators thought so.

Security and exploits are not a problem as long as you act responsibly, you can do a lot of damage as a normal user too. I don’t see a reason to restrict users.

Memory — Clearing linux caches without root privileges, 1) I/the user does not have root privileges. Can the system administrator do anything to allow normal users run the command above? 2) The calls to drop caches are from within a shell script, and running the whole script with superuser privileges is not an option. For example because there are multiple …

Unix & Linux: How does the administrator/root/superuser

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Difference between root account and administrative account

Disabling root

You have to have a root account. The only things you can do with it, in terms of «disabling» it, are:

sudo — as user root

Remember that when a user with «administrative privileges» is making use of sudo they’re running commands with elevated privileges as the user root!

You can see that this is true with a simple ps command:

$ sudo sh -c "ps -eaf | grep [s]udo" root 2625 26757 0 04:19 pts/10 00:00:00 sudo sh -c ps -eaf | grep [s]udo 

The above shows that when the ps command is executed, you’re effectively the user root.

Booting

Also when booting into a system in single user mode (from GRUB), you’ll need to login using the root account. Typically you’re passing either the word single to GRUB or the number 1 .

What sudo permissions do I have?

On a system where one has been given sudo permissions you can use the command sudo -l to see what rights you do have. These are not a complete set of everyone’s rights, just the user that’s running the command.

$ sudo -l Matching Defaults entries for saml on this host: env_reset, env_keep="COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS", env_keep+="MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE", env_keep+="LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES", env_keep+="LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE", env_keep+="LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY", secure_path=/sbin\:/bin\:/usr/sbin\:/usr/bin User saml may run the following commands on this host: (ALL) ALL (root) NOPASSWD: /usr/lib/jupiter/scripts/bluetooth, (root) /usr/lib/jupiter/scripts/cpu-control, (root) /usr/lib/jupiter/scripts/resolutions, (root) /usr/lib/jupiter/scripts/rotate, (root) /usr/lib/jupiter/scripts/touchpad, (root) /usr/lib/jupiter/scripts/vga-out, (root) /usr/lib/jupiter/scripts/wifi 

NOTE: The commands one’s been granted access to are everything after the line, «User saml may run the following . «.

Limiting access via sudo

Sudo has a fairly rich facility for limiting access to specific commands, groups of commands, specific users, and/or specific groups of users. There are some caveats however with sudo .

You can grant full access to everything with this line in /etc/sudoers :

You could also give a user what appears to be simple access to vim certain files:

This would be a huge mistake however, since many editors such as vim allow you to invoke a subshell from within them. So the user aaditya would be able to gain access to a shell with root permissions, even if the sudo permissions didn’t intend for that to happen.

An administrative account and root are by no means the same. Other than what goldilocks and slm mentioned you should also know that root can significantly limit what the sudo user is allowed to do on root ‘s behalf (see man sudoers for examples). This is especially useful when a senior sysadmin wants to delegate some administration tasks to a junior admin without granting them full access. After all, a user with full sudo access can hijack the root account.

Unix & Linux: How does the administrator/root/superuser, Unix & Linux : How does the administrator/root/superuser work in Linux?Helpful? Please support me on Patreon: https://www.patreon.com/roelvandepaarWith thank

Why there is always a root account in any OS?

That you found a root or Adminstrator account in every OS you looked at is just coincidence (or maybe a result of being new to this all). You don’t need that kind of super-user in an OS and many OS don’t have such a user or any concept of user at all. e.g. MSDOS.

If you (as the OS manifacturer) want to prevent all programs from doing everything without restriction, you need some way to require and allow privileges. There are many ways of doing this (flipping a switch on the front panel of a computer, inserting a card, logging in with super-user credentials).

The checks for this should be build into the OS. But the actual activation can be made depending on the circumstances. At install time, at activation at the users site, whatever is convenient, (or what the customer expects).

Not having a super-user (or other means to limit access to potentially destructive operations) can be considered user unfriendly as there is nothing between starting a (downloaded) program and it wiping your whole disk.

You don’t need such a super-user, but once the mechanism is there (and correctly installed) you are better of using it. But then in order to elevate the privileges when circumstances require it you need some mechanism to check whether you are allowed to do get this «elevation». Logging in as root does the trick and is software only. If every computer in the world would have a switch on the front of the machine for super-user mode (not so secure if someone has physical access to your computer), or a secure-card slot and corresponding card, that could be used as a generic mechanism as well (but it would be difficult to download such a secure-card together with the installable ISO of your Linux, and thus less convenient).

Users in Linux System Administration, Users are accounts that can be used to login into a system. Each user is identified by a unique identification number or UID by the system. All the information of users in a system are stored in /etc/passwd file. The hashed passwords for users are stored in /etc/shadow file. Users can be divided into …

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