I installed Ubuntu 11.10 with a username fooname. And then I did something like  sudo usermod -G vboxsf fooname   Then, guess what: no one is a sudoer. How can fooname be back as a sudoer?  In addition, what should I have executed to ADD fooname to the group vboxsf?
2318
I clean-installed Ubuntu 11.10 today, and then installed VirtualBox.  This required me to add myself to the vboxusers group, and since 11.10 seems to no longer have a graphical app to add users to a group, I ran the following command:  sudo usermod -G vboxusers stephane   This is a problem.  I now see what I should have run instead is:  sudo usermod -aG vboxusers stephane   The end result is I'm no longer in the groups I should be in.  Including whatever group is required to run "sudo".  When I run any command as sudo now, I get the following:  $ sudo ls [sudo] password for stephane:  stephane is not in the sudoers file.  This incident will be reported.   Is there a way to fix this, or do I need to re-install from scratch again?
80757
How does sudo work internally? How is it possible that it can become root without having the root password, unlike su? What syscalls, etc. are involved in the process? Is it not a gaping security hole in Linux (e.g. why couldn't I compile a heavily-patched sudo that just did whatever regular sudo did, but didn't ask for the unprivileged user's password)?  I have read . I have also read  but despite the title, they mainly deal with the differences between su and sudo.
23068
I need to run something as sudo without a password, so I used visudo and added this to my sudoers file:  MYUSERNAME ALL = NOPASSWD: /path/to/my/program   Then I tried it out:  $ sudo /path/to/my/program [sudo] password for MYUSERNAME:    Why does it ask for a password? How can I run/use commands as root with a non-root user, without asking for a password?
40697
When I installed the latest update of Ubuntu, I was asked for the username but I do not remember what my username is. How do I find out what my username is?
383
I updated to Ubuntu 20.04. When I use the default terminal, everything is fine. But if try to use terminator, I cannot use sudo. I get permission denied. Again, only when using terminator.  How can I sudo from the terminator? I really would like to continue to use a terminator.  Edit: I just also noted that it cannot find make either. I guess it's all messed up. I'll try to uninstall it and install again I guess.
9456
I accidentally changed /var owner/group to my username and then changed it back to root, but not all the /var folders' owners are root, so is there anyway to change back owner/group of files/folders to default state?  Or at least those files/folders that are created by packages?
123735
When I use the sudo command I get an error message.  sudo: /etc/sudoers is world writable sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin   If I try to use chmod on sudoers I get the message "Operation not permitted". Can someone help me fix things so sudo works again?
93990
I installed Ubuntu on my PC. To log in, I use the username and password I created during installation. Does this mean I am a root user? If yes, then how do I become non-root? It looks like non-root user is more secure than admin user.
88675
When I attempt to perform certain actions within ubuntu I am asked to authenticate with a root user, but ubuntu doesn't give me options for which root user, it just specifies it as the user that set up my machine. I was wondering how to go about changing which user it selects to run the authentication?  For instance, if I want to install software from the Ubuntu Software Center I am asked to authenticate with user X and I would like to change that to be user Y globally.  I am also aware that I can just run things with sudo from the command line, but I don't want to have to do that.  I'm using ubuntu 14.04. And user Y is in the sudoers file and as of now user X is not.
45461
Installed  by using install script and something crashed. Now I'm only member of my own group and lp.  Which are the default groups for users in for example Ubuntu 12.10? ?  Out of curiosity, is there some place where this information is logged? For example, some log file showing which groups my user was on previous boot? Is this information, (which groups are default), documented somewhere?
118187
How do I change my logname?For e.g: xyz@ubuntu in the terminal how do I change xyz? I have tried this command   usermod -l *newname* -d /home/*newname* -m *oldname*   but that gave me an error user xyz is currently used by process PID  Command line solutions are appreciated.
1809
In /etc/sudoers I see this:  # Allow members of group sudo to execute any command after they have # provided their password # (Note that later entries override this, so you might need to move # it further down) %sudo ALL=(ALL) ALL   So how do I add a user to that sudo group?
68265
I'm looking for a good, consistent and easy way to do a report of sudoers permissions for every user and group on the system. For users, I want the report to include permissions granted via group membership.
32466
When you want to create a bootable usb memory stick, then you must identify as a sudoer. Why is that? I have no difficulty understanding why unprivileged users shouldn't be allowed to fiddle with the installed system, but why shouldn't you be allowed to copy grub onto the memory stick if you have write access to it?
74123
Whenever I issue command sudo apt-get install foo it does not ask for password. is it because of user groups?  How to make it prompt for password?  Edit: My sudoers file   apple@Ascension:~$ sudo cat /etc/sudoers # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults    env_reset  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  #includedir /etc/sudoers.d ALL ALL=(ALL) NOPASSWD:ALL ALL ALL=(ALL) NOPASSWD:ALL ALL ALL=(ALL) NOPASSWD:ALL
62178
I am a user of Ubuntu with not much experience and I have been using sudo.  What does sudo !! do and how?
102850
I am trying to grant sudo privileges to a user of a CentOS 7 devbox by typing gpasswd -a user wheel, but the attempt is failing.  What am I doing wrong?    Here is what I typed:    I discovered that the user is not in the wheel group as follows:    [user@localhost git]$ sudo yum install git [sudo] password for user:  Sorry, try again. [sudo] password for user:  Sorry, try again. [sudo] password for user:  user is not in the sudoers file.  This incident will be reported.   I then logged in as root and typed the following to add the user to the wheel group:    [user@localhost git]$ su - Password:  Last login: Thu Aug 20 17:11:31 PDT 2015 on pts/0 [root@localhost ~]# gpasswd -a user wheel Adding user user to group wheel [root@localhost ~]# exit logout   I finally tried to use the sudo command again but it failed as follows:    [user@localhost git]$ sudo yum install git [sudo] password for user:  user is not in the sudoers file.  This incident will be reported. [user@localhost git]$