One trick with sudo is to use it to run the su command. When adding a new user there is an option to create them as an administrator, in which case they will also be able to run superuser commands with sudo. You’ve been introduced to some widely used terminology (and synonyms) that you might come across online, and have gained an insight into some of the key parts of a typical shell command. These days there’s a far better pager that you should use instead: because it replaces more, the programmers decided to call it less. In this section you’ve learnt about the dangers of the root account, and how modern Linux systems like Ubuntu try to reduce the risk of danger by using sudo. In theory you could even hook up one of those old 1970s terminals to a modern Linux box, and access the shell through that. That gives us a much easier way to switch to the etc directory, no matter where we currently are in the file system: It also gives us another way to get back to your home directory, and even to the folders within it. Give them a try to see the difference between them. In fact it’s usually referred to as the prompt, and you might sometimes see instructions that say “bring up a prompt”, “open a command prompt”, “at the bash prompt” or similar. *. The uname command, short for Unix Name, will print detailed information about your Linux system like the machine name, operating system, kernel, and so on. You might be tempted to just hit the Caps Lock key and use upper case for all your file names. If you accidental freeze your terminal by using Ctrl+S, simply undo this with the unfreeze Ctrl+Q. A long chain of commands might look intimidating at first, but remember that you can break even the longest chain down into individual commands (and look at their man pages) to get a better understanding of what it’s doing. We could cd into dir1 then use mv combined.txt .. to say “move combined.txt into the parent directory”. Surely that can’t be right? This command is quite complex with a long list of functions such as adding new files into an existing archive, listing the content of an archive, extracting the content from an archive, and many more. This will delete everything and there is no undo. If you are asked to use su with a username then (if you have the password) you will have access to all the files of that user, and could accidentally delete or modify them. If anyone asks you to use su, be wary. Even on machines from the 1970s, running hundreds of terminals across glacially slow network connections (by today’s standards), users were still able to interact with programs quickly and efficiently. In short, root can do just about anything, skipping easily round the safeguards that are usually put in place to stop users from overstepping their bounds. In this next section we’re going to start deleting files and folders. A question mark ("?") Now that we’ve got a few files, let’s look at the sort of day-to-day tasks you might need to perform on them. Let’s start with a simple question. However, rmdir only allows you to delete empty directories. A command’s position in the list is not representative of its usefulness or simplicity. If you only want to delete the directory — as an alternative to rmdir — use rm -r. Note: Be very careful with this command and double-check which directory you are in. One important concept to understand is that the shell has a notion of a default location in which any file operations will take place. Will the computer complain, because the file already exists? Programmers often use this command when they need to make program alterations instead of rewriting the entire source code. It’s as though you’ve connected a pipe between one command’s output and the next command’s input, so much so that this process is actually referred to as piping the data from one command to another. An errant space character in your command can change it completely: rm t* means “delete all the files starting with t”, whereas rm t * means "delete the file t as well as any file whose name consists of zero or more characters, which would be everything in the directory! Instead they have a single unified file system, and individual drives can be attached (“mounted”) to whatever location in the file system makes most sense. If you’re ever in any doubt, the pwd command will tell you exactly what the current working directory is. The Linux operating systems are based on Linux kernel. In practice it works like this: The sudo command, when used without any options, will assume that the first parameter is a command for it to run with superuser privileges.