Coming from Windows, the Linux filesystem looks alien at first: no drive letters, no C:\, and a bunch of directories with cryptic three-letter names. But there's a simple logic to it — everything hangs off one root directory called /, and each top-level folder has a specific job.

Once you learn what lives where, navigating Linux stops feeling random.

One tree, one root

Windows gives every drive a letter. Linux mounts every disk, USB stick, and network share into a single tree starting at / (the root directory). Your second hard drive isn't D: — it might appear at /mnt/data. Your USB stick shows up somewhere like /media/yourname/usb.

This is called the Filesystem Hierarchy Standard (FHS), and almost every distro follows it.

The directories you'll actually use

  • /home — your personal files. Each user gets /home/username (often written ~). This is your Documents, Downloads, and config files. Back this up and you've saved what matters.
  • /etc — system-wide configuration files. Nginx configs, network settings, user accounts (/etc/passwd). Text files, editable, and the reason Linux servers are so scriptable.
  • /var — data that changes constantly: logs (/var/log), databases, website content, package caches. When a server disk fills up, /var/log is a prime suspect.
  • /root — the root user's home directory. Not the same as /. Regular users can't enter it.
  • /usr — installed programs and libraries (/usr/bin, /usr/lib). You rarely edit anything here; the package manager owns it.
  • /bin and /sbin — essential commands. On modern distros these are just symlinks into /usr/bin and /usr/sbin.
  • /tmp — temporary files, wiped on reboot. Never store anything you care about here.
  • /boot — the kernel and bootloader files. Small, important, leave it alone.
  • /dev — devices represented as files: /dev/sda is a disk, /dev/null swallows output. The Unix "everything is a file" philosophy, literally.
  • /proc and /sys — virtual windows into the running kernel. /proc/cpuinfo shows your CPU details; nothing here is a real file on disk.
  • /mnt and /media — mount points for temporary (/mnt) and removable (/media) storage.

Permissions in 30 seconds

Every file has an owner, a group, and permission bits for read/write/execute. ls -l shows them:

-rw-r--r-- 1 user user 4096 Nov 2 notes.txt

The first ten characters are the type and permissions; our chmod calculator translates the numbers (644, 755) into plain English if the letters confuse you.

Paths: absolute vs relative

An absolute path starts at the root: /home/user/notes.txt. A relative path starts from wherever you are: documents/notes.txt. Two shortcuts you'll type daily:

  • .. — the directory above the current one (cd .. goes up)
  • ~ — your home directory (cd ~/Downloads works from anywhere)

Try it yourself 

ls / # the whole top-level map df -h # which disks are mounted where, and how full they are du -sh /var/log # how much space a directory uses find /etc -name "*.conf" | head # config files in the wild

Spend ten minutes clicking through /etc, /var/log, and your home directory, and the layout will stick for life. For the next step, our guides on file permissions and the find command build directly on this map.