The superuser is a privileged user with unrestricted access to all files and commands. The superuser has the special UID (user ID) 0. You need to become super user (root) only when tasks need root permissions. Here is how to become a super user:
At the shell prompt type su - and press enter key, when prompted for password supply root user password:
$ su -
Sample outputs:
password: #
The su command requests appropriate user credentials via PAM and switches oo that user ID (the default user is the superuser). A shell is then executed. Type exit or press CTRL+D to exit from superuser session, enter:
# exit
su: Sorry for normal user account error and solution
If you get an error that read as follows:
su: Sorry for normal user account.
You can fix this problem by adding user account to the wheel group. PAM is used to set the policy su will use. In particular, by default only users in the wheel group can switch to UID 0 (root). This group requirement may be changed by modifying the pam_group section of /etc/pam.d/su file. wheel is a special group for system administration purpose. Add your normal user to this group using the pw command. The syntax is:
pw user mod username -G wheel
In this example add a user called vivek to the group called wheel, enter:
# pw user mod vivek -G wheel
# groups vivek
Sample outputs:
vivek wheel
You can disable this behavior complete for all users (not recommended until and unless you trust ALL of your users). Open pam configuration file for su using a text editor such as vi or vim:
# vi /etc/pam.d/su
Find the following line and comment it out:
auth requisite pam_group.so no_warn group=wheel root_only fail_safe ruser
Replace with:
#auth requisite pam_group.so no_warn group=wheel root_only fail_safe ruser
Save and close the file. Now all users can use su command to become root or superuser.
You should follow me on twitter here or grab rss feed to keep track of new changes.
Featured Articles:
- 30 Handy Bash Shell Aliases For Linux / Unix / Mac OS X
- Top 30 Nmap Command Examples For Sys/Network Admins
- 25 PHP Security Best Practices For Sys Admins
- 20 Linux System Monitoring Tools Every SysAdmin Should Know
- 20 Linux Server Hardening Security Tips
- Linux: 20 Iptables Examples For New SysAdmins
- Top 20 OpenSSH Server Best Security Practices
- Top 20 Nginx WebServer Best Security Practices
- 20 Examples: Make Sure Unix / Linux Configuration Files Are Free From Syntax Errors
- 15 Greatest Open Source Terminal Applications Of 2012
- My 10 UNIX Command Line Mistakes
- Top 10 Open Source Web-Based Project Management Software
- Top 5 Email Client For Linux, Mac OS X, and Windows Users
- The Novice Guide To Buying A Linux Laptop
![Learning and Mastering the Linux VI / VIM Editor [ PDF version ]](http://s13.cyberciti.org/images/shared/rp/3/6.jpg)
{ 10 comments… read them below or add one }
You do not necessiarily need to enable root (it COULD be a a risk to open that acoount up ;-)
try ‘sudo su’ and you will be promoted to root WITHOUT enabling root!
FreeBSD : Using sudo
You are correct. For those who are not familiar with sudo under FreeBSD here is small how-to:
1) What is sudo?
sudo is security tool/utility which allows a permitted user to execute a command as the superuser or another user, as specified in the sudoers (/usr/local/etc/sudoers) file. It supposes to replace traditional su command which is discussed above.
2) How do I install sudo?
By default, sudo is not installed; you can install it from ports collection or from installation media such as DVD/CDROM. However, make sure it is not installed with following command:
#pkg_info | grep sudo
If sudo package already installed it will display in output else use any one of the following method to install sudo.
Method # 1 : Install sudo from CD/DVDROM
a) Login as root user
b) Mount cdrom drive
# mount /cdrom
c) Change directory to security directory where sudo binary package is stored on disk:
# cd /cdrom/packages/security/
d) Install the sudo:
# pkg_add -v sudo*
Method # 2: Using ports (recommended)
a)Goto sudo ports directory:
# cd /usr/ports/security/sudo
b) Download, compile and install sudo:
# make install clean
Main sudo configuration file is usr/local/etc/sudoers. You can edit this file directly or use visudo command
rdl fbsd.test.com=/sbin/su
Save the file
rdl : Name of user who can execute /sbin/su command for fbsd.test.com host
Now you rdl can execute the command (when prompted for password supply rdl users password)
$ sudo /sbin/su
See su and sudo man pages for more information.
thanks, this helped me get su and sudo setup for my user account.
Thanks… as a brand new Linux user this was a HUGE help!
Very helpful.
Very helpful.
Thanks.
Thanks, it helped me tooo
Big thanks!
hey,
is there any method by which su command souldn’t ask for the password??
a question about
sudo su
does this command enable root without asking for the account password ?
therefore is it safer to enable root just to set a password so that if someone who knows your account password cannot perform sudo commands ?
or …if the ‘sudo su’ command doesnt ask for a password does it even make a difference ?
try gdb’s shortcut b some_function’ and then s’ :)@someone: can you use your VC to ssh sverer to debug(without setting up VNC)? Can you use VC to debug other language like python, Erlang, ? Do you think VC’s debugging ability also apply on very complicated problem or problems need to scale up, like map-reduce, complicated async network problem? Ppl in linux think deeper.Finally, how much time we should spend on learning our tools depends on our self-expectation. If you are aiming for F1 champion, will you save $$ on your car?