a. Background

The part of the operating system responsible for managing files and directories is called the file system. It organizes our data into files, which hold information, and directories (also called ‘folders’), which hold files or other directories.

Several commands are frequently used to create, inspect, rename, and delete files and directories. To start exploring them, we’ll go to our open shell window.

First, let’s find out where we are by running a command called pwd (which stands for ‘print working directory’). Directories are like places — at any time while we are using the shell, we are in exactly one place called our current working directory. Commands mostly read and write files in the current working directory, i.e. ‘here’, so knowing where you are before running a command is important. pwd shows you where you are:

$ pwd

/Users/nelle

Here,the computer’s response is /Users/nelle, which is Nelle’s home directory:

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Home Directory Variation

The home directory path will look different on different operating systems. On Linux, it may look like /home/nelle, and on Windows, it will be similar to C:\Documents and Settings\nelle or C:\Users\nelle. (Note that it may look slightly different for different versions of Windows.) In future examples, we’ve used Mac output as the default - Linux and Windows output may differ slightly but should be generally similar.

We will also assume that your pwd command returns your user’s home directory. If pwd returns something different, you may need to navigate there using cd or some commands in this lesson will not work as written. See Exploring Other Directories CHECK LINK for more details on the cd command.

To understand what a ‘home directory’ is, let’s have a look at how the file system as a whole is organized. For the sake of this example, we’ll be illustrating the filesystem on our scientist Nelle’s computer. After this illustration, you’ll be learning commands to explore your own filesystem, which will be constructed in a similar way, but not be exactly identical.

On Nelle’s computer, the filesystem looks like this:

The file system is made up of a root directory that contains sub-directoriestitled bin, data, users, and tmp

At the top is the root directory that holds everything else. We refer to it using a slash character, /, on its own; this character is the leading slash in /Users/nelle.

Inside that directory are several other directories:

  • bin (which is where some built-in programs are stored),
  • data (for miscellaneous data files),
  • Users (where users’ personal directories are located),
  • tmp (for temporary files that don’t need to be stored long-term), and so on.

We know that our current working directory /Users/nelle is stored inside /Users because /Users is the first part of its name. Similarly, we know that /Users is stored inside the root directory / because its name begins with /.

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Slashes

Notice that there are two meanings for the / character. When it appears at the front of a file or directory name, it refers to the root directory. When it appears inside a path, it’s just a separator.

Typically, when you open a new command prompt, you will be in your home directory to start. Because Nelle is the user in our examples here, therefore we get /Users/nelle as our home directory.

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Clearing your terminal

If your screen gets too cluttered, you can clear your terminal using the clear command. You can still access previous commands using ↑ and ↓ to move line-by-line, or by scrolling in your terminal.