Unix Filesystem Basics

Overview

Building on the introductory tour of Linux, this week deepens your understanding of the command-line interface and the structure of the Unix filesystem.
You will learn how to use shell commands effectively, explore standard directories and their purposes, understand file types (regular files, directories, devices, links), and manage users, groups, and permissions.

By the end of this week you should be able to confidently navigate the filesystem, interpret file metadata, and control access rights using the shell.

Key Concepts

The shell as an interface: command syntax, arguments, options
Command synopsis and using man pages
Standard Linux directory hierarchy (/bin, /etc, /home, /var, /proc, /dev, …)
File types: regular, directory, character/block devices, sockets, FIFOs
Hard links vs. symbolic (soft) links
Users, groups, and ownership model
File permissions: read/write/execute, chmod, chown, chgrp

Practice / Lab

Shell Exploration:
- Use man, which, type to discover command info
- Practice navigation with cd, pwd, ls -l, tree
Filesystem Walk:
- Inspect the top-level folders under /
- Explore /proc and /dev for virtual and device files
Working with Links:
- Create hard and symbolic links (ln, ln -s) and examine inode numbers with ls -i
Permissions Management:
- Check file metadata with ls -l
- Change mode and ownership (chmod, chown, chgrp)
- Experiment with umask and default file permissions
Users & Groups:
- Inspect /etc/passwd and /etc/group
- Use id, who, groups to view account information

References & Resources

Required

Optional / Enrichment

Tools

ls, cd, pwd, man, file, stat, tree
ln, chmod, chown, groups, id

Quiz (Self-check)

What is the difference between a hard link and a symbolic link?
Which directory holds configuration files for most system services?
What do the three sets of characters in rwxr-xr-- represent?
How can you find the manual page for a command?
Which virtual directory contains information about running processes?

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