Linux for Beginners

by Jason Cannon

A mischievous person could write a program that repeatedly connects to your server trying a new username and password combination each time. They can increase their odds of gaining entry by using a list of common usernames and passwords. Configuring your cloud server to not accept account passwords and to only accept SSH keys eliminates this threat.

Having an SSH key without a passphrase can allow you to automate and schedule tasks that require logging in to remote systems.

The shell is nothing more than a program that accepts your commands and executes those commands. Said another way, the shell is a command line interpreter.

The superuser on a Linux system is also called root. Anything that can be done on a server can be done by root. However, normal users can only do a subset of the things root can do. Root access is typically restricted to system administrators, but if you happen to support an application on a Linux server you may need root privileges to install, start, or stop it. There are ways to grant specific users root privileges for specific cases. This is often accomplished with the sudo -- SuperUser Do -- program.

A link is sometimes called a symlink, short for symbolic link. A link points to the location of the actual file or directory. You can operate on the link as if it were the actual file or directory. Symbolic links can be used to create shortcuts to long directory names. Another common use is to have a symlink point to the latest version of installed software as in this example.