Every file and folder on a Linux machine lives inside one tree. The tree
has exactly one root, written /. No C:, no D:, no separate drives.
/
├── etc/ # system-wide configuration
├── var/ # variable data: logs, spools, caches
├── home/ # regular users' home folders
├── root/ # the root user's home
├── tmp/ # temporary files, often wiped on reboot
├── usr/ # installed software
└── bin/ # essential command binaries
These are the most common folders that you would see directly under
/. Each one has a specific job.
/etc holds system-wide configuration./var holds data that changes while the system runs, like logs,
mail queues, and package caches. The one you'll open most is
/var/log, which is where every service writes its log files./home holds one folder per regular user account. A user named
alice gets /home/alice as her home folder, and she typically
owns everything inside it./root is the home folder of the root (administrator) user. It's
kept separate from /home so the root account can still work even
if /home is on a broken disk./tmp is scratch space. Any process can write files here, and the
contents are typically wiped on reboot. Never store anything you
want to keep./usr holds installed software: user programs in /usr/bin,
libraries in /usr/lib, documentation in /usr/share. Package
managers put most of their files here./bin holds essential command binaries needed early during boot
and system recovery, like ls, cp, and bash. On modern Linux
it's usually a symlink to /usr/bin.The others exist too (/dev, /proc, /sys, /opt, /srv, /mnt,
/media), and you'll meet them as they come up.
You met pwd in the previous topic. Run it now and you'll see
where in this tree the shell has placed you (probably /root, the
root user's home). Every path you write is either an address
starting from / (the top of this tree) or a shortcut from
wherever pwd currently reports. The next node covers those two
styles in detail.