InformIT: Red Hat Linux 7 Unleashed > Logging In and Shutting Down

Logging In and Shutting Down

Now that you are faced with the login: prompt for the first time, you may be wondering how to get into the system.

At this point on a newly installed system, there is generally only one account to log in to—the administrative account, root. This account is used to manage your system and do things like configure the system, add and remove users, software, and so on. To log in to the account, enter root at the login: prompt and press Enter. You are asked for the password you entered during installation. Enter that password at the password: prompt. The system prompt

[root@localhost] #

appears after you have successfully negotiated the login. The system prompt tells you two things: you are logged in as root, and in this case, your machine is called localhost. If you named your machine during the installation process, your host name will appear instead of localhost. If you decided to set up other users during the install process you can also log in with those usernames and passwords.

To shut down the system from a terminal session, sign in or su to the root account. Then type /sbin/shutdown -r now. It may take several moments for all processes to be terminated, and then Linux will shut down. The computer will reboot itself. If you are in front of the console, a faster alternative to this is to press Ctrl+Alt+Delete to shut down. Please be patient as it may take a couple of minutes for Linux to terminate.

The su command can be used to run root commands from a normal user account. For example, to run any root command as a normal user you would only have to type su –c command where command is any command. You can also use su to switch user. The format of this command would be su – user where user is any user that exists on the system. The hyphen logs you in to that user's home directory as the current working directory.

You can also shut down the system to a halt (that is, it will shut down and not reboot the system). The system will be unavailable until power-cycled or rebooted with Ctrl+Alt+Delete. This can be useful if you need to power down the system and move it to a different location, for example. To do this, type /sbin/shutdown -h now when signed into or su-ed to the root account. Linux will shut itself down then display the message "System halted". At this point you can power down the computer. It is important to note that you cannot just switch off a Linux system. The system must be allowed to unmount all partitions to provide for a clean startup. Just switching the system off can cause corruption of data on the hard drive.

It is probably a good idea to only shut down the system when you are at the console. Although you can shut it down remotely via a shell session, if anything goes wrong and the system does not restart properly, the system will be unavailable until action is taken at the system unit.

Upon system bootup, Linux will start automatically if it is the default OS defined in LILO, and load all necessary services including networking support and Internet services.

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