su is a utility to run a shell or other command as another user (root by default).
69
votes
7answers
7k views
Which is the safest way to get root privileges: sudo, su or login?
I would like to have the root account in safety even if my unprivileged user is compromised.
On Ubuntu you can only use sudo for "security reasons" by default. However I am not sure it is any safer ...
8
votes
2answers
2k views
When do su and sudo use different passwords?
I am able to run anything using sudo; my password is accepted. But whenever I try to do su from a shell, it fails with:
su: incorrect password
What can the problem be?
56
votes
2answers
5k views
Why do we use su - and not just su?
I don't understand why su - is preferred over su to login as root.
7
votes
1answer
547 views
What's the difference between sudo su - and sudo su --
When I am working on our RHEL machines, I use sudo su - to switch to being root. One day, a typo meant I typed sudo su -- instead - it seems to me that everything was the same as with a single hyphen, ...
6
votes
3answers
990 views
sudo permission denied but su grants permission
this is the first occurrence where su was required for me.
I read an article about changing the value in /sys/devices/virtual/backlight/acpi_video0/brightness to alter my laptop's screen brightness.
...
47
votes
5answers
9k views
Where did the “wheel” group get its name?
The wheel group on *nix computers typically refers to the group with some sort of root-like access. I've heard that on some *nixes it's the group of users with the right to run su, but on Linux that ...
4
votes
2answers
2k views
.bash_profile not sourced when running su
I have a user, say user1, which has modifications to its .bash_profile, one of them changing the PATH, e.g.: export PATH=/some/place:$PATH. This change works fine if I log on as user1 or do a su - ...
4
votes
2answers
684 views
Alternative to su/sudo on barebone system
I'd like to run some unit tests in a barebone chroot jail on Solaris. There's no su or sudo, and a copy of su (with libpam.so.1) just returns exit code 1 without any output, with or without ...
3
votes
3answers
449 views
linux launch script /etc/init with a specific user
I've created a script in /etc/init/mms-agent.conf :
start on runlevel [2345]
stop on runlevel [06]
exec /usr/bin/env python /home/mms/mms-agent/agent.py >> /home/mms/agent.log 2>&1
...
2
votes
3answers
462 views
Switching to superuser while shell script is running
I have a shell script that contains the following lines:
CURRENT_USER=${USER}
echo $CURRENT_USER
su
echo switch to `who am i`
Once the 2nd line is executed, the shell prompts me to enter the root ...
0
votes
4answers
1k views
Is there a difference between sudo su - root and sudo -u root -H /bin/bash?
Like title says, is there a difference between these two commands :
sudo su - root
sudo -u root -H /bin/bash
I'm using GNU/Linux, if that makes a difference.
9
votes
2answers
2k views
su vs sudo -s vs sudo bash
What is the difference between the following commands:
su
sudo -s
sudo bash
I know for su I need to know the root password, and for sudo I have to be in the sudoers file, but once executed what is ...
3
votes
2answers
778 views
`$XAUTHORITY` appears from 'nowhere' on su+tmux
When I switched from su+bash to su+tmux+zsh I noticed that I get $XAUTHORITY variable defined as /root/.xauthXXXXXX where XXXXXX are 6 random alphanumeric characters. With previous configuration X ...
3
votes
2answers
2k views
su vs su - (on Debian): why is PATH the same?
I know what should be the difference between su and su -, but in my system (debian testing) for example PATH is the same:
[root]# su
[root]# echo $PATH
...
