Login, Logout and shutdown the linux system

I think you have installed the Linux on your system properly. Now the next step is logging in, out and shutdown of your system.

It is very simple when you have installed a GUI based Linux distro. But if you dont have the GUI based system then as you start your system then a login prompt will appear on the black screen.

Here you type the user name which password you know and press 'enter' now there will be a password prompt then give the respected user password you will get logged in.

If you logged in with 'root' user then you are the super user having all the authentication of the system. But if you are not a 'root' user then you have the limited rights assigned to the user with which you logged in. If you want to switch to the 'root' user then no problem.

Write 'su' on the command prompt and press 'enter'
then give the root password you will get in with root account....

*you can enter in other user mode even by su followed by the user name and give the password of that user.

To come back on the previous level(or logging out of root account) use 'exit' command.

To change the root password do as below:

root@ubuntu:/home/sachin# passwd
Enter new UNIX password: your password
Retype new UNIX password: repeat above password
passwd: password updated successfully

Now you have new root password.

Shutting down your Linux system:

You can shutdown a Linux by using the 'ALT+CTRL+DEL' key combination but it does not work in every system it depends on the 'init' program. But the following are the commands which generally works on most of the system if you are logged in as root user.

shutdown -h now --will shutdown your system immediately
shutdown -P now -- will work as above command
shutdown -r now --will make your system to reboot immediately
shutdown -r +10 --will make your system to reboot in 10 minutes
shutdown -r 14:00 --will make your system down and reboot at 2:00pm