Questions related to the sudo command that allows users to run programs with the privileges of a different user (normally the root user).

learn more… | top users | synonyms (1)

110
votes
8answers
54k views

How to avoid using sudo when working in /var/www?

I want to stop having to use sudo everytime I work in /var/www. How can I do that? I simply want to put all of my sites into this directory and work with them without too much pain.
18
votes
7answers
14k views

Nothing shows up in the terminal when I type my password

When I'm about to install a program in the terminal it wants the password: [sudo] password for xxx: But when I want to type my password it happens nothing. What should I do?
40
votes
3answers
34k views

How do I add myself back as a sudo user?

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 ...
62
votes
2answers
11k views

Why should users never use normal sudo to start graphical applications?

I've read the comunity "RootSudo" documentation and am interested in this line: You should never use normal sudo to start graphical applications as Root. Why? What is the difference? Please ...
78
votes
8answers
38k views

What is the difference between “gksudo nautilus” and “sudo nautilus”?

I've been using gksudo nautilus and sudo nautilus through Alt+F2. What's the difference? They look very similar!
26
votes
6answers
13k views

What if I accidentally run command “chmod -R” on system directories (/, /etc, …)

I accidently ran sudo chmod 755 -R / instead of sudo chmod 755 -R ./ I stopped it after few seconds, but now there is some problems such as sudo: must be setuid root How can I revert ...
71
votes
5answers
39k views

When using sudo with redirection, I get 'permission denied'

When using sudo to allow edits to files, I regularly get 'permission denied'. For example, my mouse is jittery and sluggish, so I want to disable polling: sudo echo "options drm_kms_helper poll=N"&...
115
votes
1answer
141k views

How do I run specific sudo commands without a password?

On one particular machine I often need to run sudo commands every now and then. I am fine with entering password on sudo in most of the cases. However there are three sudo commands I want to run ...
506
votes
6answers
1.6m views

How can I add a new user as sudoer using the command line?

After I add a user using adduser, I can't see it via System->Administration->Users and Groups unless I logout and then login again. Is that normal? Also, can I set a newly added user as a ...
147
votes
12answers
188k views

How to modify a invalid /etc/sudoers file? It throws out an error and not allowing me to edit again

How do I edit an invalid visudo file? Here is what happens: $ sudo visudo >>> /etc/sudoers: syntax error near line 28 <<< sudo: parse error in /etc/sudoers near line 28 sudo: no ...
274
votes
18answers
323k views

Error message when I run sudo: unable to resolve host (none)

I have this issue on AWS on some servers. Whenever I run sudo the terminal is stuck doing seemingly nothing, until it finally spits out this error message. My terminal looks like this: ubuntu@(none):~...
72
votes
5answers
146k views

What are the differences between “su”, “sudo -s”, “sudo -i”, “sudo su”?

I already read it from manual but I can't see difference.. su - change user ID or become superuser sudo -s [command] The -s (shell) option runs the shell specified by the SHELL environment ...
108
votes
5answers
198k views

Execute sudo without Password?

Inspired by this question.... I am the sole person using my system with 12.04. Every time I issue a sudo command; the system asks for the user password (which is good in its own way). However I was ...
87
votes
4answers
123k views

How do I sudo a command in a script without being asked for a password?

I want to turn my system on automatically every day. So I use the below code in my Python script, but sudo asks me for a password every time: os.system('sudo sh -c "echo date \'+%s\' -d \'+ \ ...
20
votes
7answers
27k views

su command + authentication failure

I am having problems with the su command. I know my password and I am typing it correctly but su indicates authentication failure. So I checked on the internet and then went into recovery mode and ...
25
votes
3answers
9k views

Redirect the output using `sudo` [duplicate]

I have a small question regarding using sudo with output redirect >. To enable IP forwrding, someone can use the command: echo 1 > /proc/sys/net/ipv4/ip_forward Executing this command will ...
9
votes
4answers
90k views

'Some index files failed to download' while updating

When running sudo apt-get update I get these following errors: Err archive.ubuntu.com quantal InRelease Err archive.ubuntu.com quantal-updates InRelease Err archive.ubuntu.com quantal-backports ...
28
votes
6answers
68k views

How to run an application using sudo without a password?

... but still be required for applications that need admin privilegies? In order to allow the following: $ apache2ctl restart httpd not running, trying to start (13)Permission denied: make_sock: ...
3
votes
1answer
1k views

Changed permissions of / to user

I stupidly ran sudo chown -R carlos:carlos / and carlos is my user. This changed all files to be Carlos and I could not boot up again (because the root files were now owned by #1000) and I cant get ...
115
votes
5answers
269k views

How do I add a user to the “sudo” group?

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 ...
62
votes
3answers
15k views

When to use pkexec vs. gksu/gksudo?

There are two general ways to run applications graphically as root (or, more generally, as another user). Programs like gksu, gksudo, and kdesudo are graphical frontends for sudo. In contrast, pkexec ...
9
votes
4answers
27k views

How to fix sudo after “chmod -R 777 /usr/bin”?

I enetered chmod -R 777 /usr/bin and now sudo is not working. It is giving error that sudo must be setuid root. On looking via Google, some advice said to run chown root:root /usr/bin/sudo chmod ...
117
votes
3answers
256k views

How to run sudo command with no password?

How does the ubuntu user on the AWS images for Ubuntu Server 12.04 have passwordless sudo for all commands when there is no configuration for it in /etc/sudoers? I'm using Ubuntu server 12.04 on ...
33
votes
5answers
13k views

How to NOT become a root user? Are administrators root?

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 ...
15
votes
7answers
13k views

What are the benefits of sudo over su?

What is the actual benefit that Ubuntu (or Debian derivatives) achieve by disabling root user? Everywhere I read, it says to prevent unintentional damages for inexperienced users. I want to know what ...
102
votes
1answer
136k views

'sudo su -' vs 'sudo -i' vs 'sudo /bin/bash' - when does it matter which is used, or does it matter at all?

When I'm doing something that requires root be typed in dozens of times in a row, I prefer to switch my session to a root session. In the various tutorials and instructions I have used on the Internet,...
34
votes
4answers
502k views

How do I login as root?

I want to login as root, but when I enter sudo -s and enter password, this message is shown: "you are not in sudoers file", and when I enter su and enter password, this is shown: "...
32
votes
5answers
45k views

Shutdown from terminal without entering password?

I have desktop edition of Ubuntu. I like the Terminal so that that I prefer to shutdown my computer with the shutdown command. However when I type shutdown now it prompts me to enter my password.Is ...
13
votes
3answers
38k views

Mount VirtualBox SharedFolder in Ubuntu VM on boot

I have a Ubuntu VM running in VirtualBox. I have a Shared Folder set up as myshare I have a folder created in my home directory (~/jamesw) as host. using the line sudo mount -t vboxsf myshare host ...
4
votes
5answers
105k views

How can I determine the sudo password?

What is the default password of the sudo? I visit some forums, it tells that the default password is password, but it doesn't work, how can I determine the password?
24
votes
6answers
43k views

sudo error, is mode 0777, should be 0440

I am getting sudo errors, how do I fix this error? sudo: /etc/sudoers is mode 0777, should be 0440 sudo: no valid sudoers sources found, quitting
12
votes
4answers
6k views

How to prevent system applications (like the Software Center) from asking for password?

I'd like Software Center, Update Manager and some other system management applications to work without asking for password (like sudo does if configured with NOPASSWD) but only asking for a ...
77
votes
4answers
403k views

How do I grant sudo privileges to an existing user? [duplicate]

I want to grant a newly created user sudo privileges in Ubuntu. I tried sudo adduser hduser admin but it says no admin group exists. How can I do it?
21
votes
1answer
6k views

How to configure pkexec?

Reading these questions and answers: When to use pkexec vs. gksu/gksudo? Why is gksu no longer installed by default? brought me another one that will create problems for new users of that command:...
26
votes
5answers
41k views

Environment variables when run with 'sudo'

As example to my question, my ~/.bashrc file contains this lines: export LD_LIBRARY_PATH=/opt/intel/mkl/lib/ia32:$LD_LIBRARY_PATH export LD_PRELOAD=/opt/intel/mkl/lib/ia32/libmkl_core.so so that ...
16
votes
7answers
39k views

How can I run an application with a GUI as admin from a non-admin user session?

I defined 2 user accounts: one with admin privilege (with sudo right) => lets call it adminuser. a 2nd one without any privilege => lets call it normaluser and I configure the autologin on this 2nd ...
19
votes
8answers
59k views

/usr/bin/sudo must be owned by uid 0 and have the setuid bit set

I have run following command accidentally sudo chown [username] -hR / Now sudo su getting error: sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set How to Solve This?
15
votes
3answers
2k views

How often is the password asked for sudo commands? Where can I set it up?

I execute quite a lot of sudo commands. I noticed that if I execute one and then another one within few minutes, the 2nd time I don't get the message: [sudo] password for my_username: but I do ...
41
votes
3answers
9k views

What are the differences between sudo, su, visudo, chroot, and gksu?

What are the differences between sudo, su, visudo, chroot, and gksu ?
22
votes
2answers
57k views

Setting the PATH so it applies to all users, including root/sudo

The instructions in How do I set PATH variables for all users on a server? work to set the PATH for all 'normal' users. However, if I do sudo -s and then printenv PATH the updated path is not shown. I'...
22
votes
4answers
15k views

Is the difference between sudo and gksu the same as the difference between sudo -i and sudo -s?

Is the difference between sudo cmd and gksu cmd, the same as the difference between starting a shell with sudo -i and sudo -s? ... or put another way, Is sudo cmd the same as sudo -i cmd and gksu ...
13
votes
3answers
8k views

sudoers - simple explanation requested

Everytime I want to be able to run something that requires me to be a sudoer too many times, I need to google for the formatting of /etc/sudoers to remind me again what exactly is the proper way to ...
56
votes
3answers
29k views

What is the difference between the 'sudo' and 'admin' group?

I noticed that two groups are granted similar-looking permissions in /etc/sudoers: # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL # Allow members of group sudo to execute ...
17
votes
2answers
12k views

How do I prevent PolicyKit from asking for a password?

For years, I've had the following in my sudoers file: scott ALL=NOPASSWD: ALL For those who don't know, this prevents sudo and friends (gksudo, etc.) from asking for a password. However, over the ...
14
votes
1answer
16k views

Cannot lock '/etc/group' in recovery mode

I've currently booted into recovery mode, because I removed my sole user from admin :/ When I run adduser oadams admin, I get gpasswd: cannot lock /etc/group; try again later. For what it's worth, ...
8
votes
2answers
8k views

Regain Sudo rights after removing from admin group [duplicate]

I accidentally removed myself from the admin group when editing the user. Now I can no longer use sudo. The error says: ber is not in the sudoers file. This incident will be reported. I booted up ...
4
votes
2answers
12k views

Won't execute terminal commands

I have been using Ubuntu 12.04 for quite a while and have never had a problem come at me out of the blue like this. I'm trying to install python 3.2 on my Ubuntu system and every time I run the code ...
73
votes
4answers
22k views

Aliases not available when using sudo

I was playing around with aliases today and I noticed that aliases don't seem to be available whilst using sudo: danny@kaon:~$ alias alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' ...
19
votes
2answers
13k views

warning message at command line `sudo`

Everytime I try to sudo something at the terminal, I get a warning message: alexandre@XPS-15Z $ sudo mount file.iso /mnt/ -o loop [sudo] password for alexandre: no talloc stackframe at ../source3/...
4
votes
3answers
14k views

'sudo' not working after changing the permissions of '/usr' directory

Recently I had to change the folder permissions of /usr folder. Now the whole sudo is not working. If I try to update my system using this command: sudo apt-get update I get the following message: ...