1.1. The Filesystem¶
The filesystem is how your operating system organizes data to be stored and retrieved. A file has two key properties: a filename (usually written as one word) and a path. The path specifies the location of a file on the computer. For exam- ple, a file on my Windows 10 laptop has the filename project.docx in the path C::raw-latex:`\Users`:raw-latex:`\Al`:raw-latex:`\Documents`. The part of the filename after the last period is the file’s extension and tells you a file’s type. The filename project.docx is a Word docu- ment, and Users, Al, and Documents all refer to folders (also called directories). Folders can contain files and other folders. For example, project.docx is in the Documents folder, which is in the Al folder, which is in the Users folder. Figure 2-1 shows this folder organization.
Figure 2-1: A file in a hierarchy of folders
The C: part of the path is the root folder, which contains all other folders. On Windows, the root folder is named C: and is also called the C: drive. On macOS and Linux, the root folder is /. In this book, I’ll use the Windows- style root folder, C:. If you’re entering the interactive shell examples on macOS or Linux, enter / instead.
Additional volumes, such as a DVD drive or USB flash drive, will appear differently on different operating systems. On Windows, they appear as new, lettered root drives, such as D: or E:. On macOS, they appear as new folders within the /Volumes folder. On Linux, they appear as new folders within the /mnt (“mount”) folder. Note that folder names and filenames are not case sensitive on Windows and macOS, but they’re case sensitive on Linux.