I tried to su
to root so I could install lights, but I get an authentication error when I try:
user@host:~$ su
Password:
su: Authentication failure
I tried to su
to root so I could install lights, but I get an authentication error when I try:
user@host:~$ su
Password:
su: Authentication failure
The root account is disabled by default in Ubuntu, so there is no root password, that's why su
fails with an authentication error.
Use sudo
to become root:
sudo -i
sudo chmod +s /bin/su
If su
doesn't work, I do this (in bash):
user@host:~$ sudo bash
root@host:~# su
root@host:/home/user#
Voila! You are now root!
A shortcut for this would be sudo su
. In this case given that you are a member of /etc/sudoers
with all privileges, then you would only need your user's password.
sudo bash
you are running bash as root, but '~' still points to /home/user or wherever your user's home directory is. So you are not quite root. A shortcut for this would be sudo su
Apr 21, 2014 at 12:59
sudo
is preserving some environment variables. Instead of sudo bash
it's better to just use sudo -i
.
sudo -i
then su
. But I would totally agree that in most cases just using sudo should be fine. That is what I usually do. Unless I need root. Then I use su
.
Apr 23, 2014 at 16:31
sudo -i
already is enough. Seriously, you just sudo su
or sudo -i
, this is enough to become root (no need to "su" again)...
Open root with sudo -s
and when it's in this mode type:
passwd
Then, choose password. This password will be for su
command.
You are getting Authentication failure
because you are trying to become root which is disabled by default in all versions of Ubuntu. This can be easily circumvented in two ways:
Instead of su
use sudo -i
or better yet, append to any command sudo
in the way of:
sudo apt-get update
[sudo] password for braiam:
I wouldn't recommend enabling root, since it could raise a security concern, for example, if you use any service exposed to the web.
Use sudo your_command
in place of su.
ie
sudo apt-get install "program to install"