1.1The Filesystem Hierarchy

Linux organizes everything as files in a single directory tree starting from the root /. There is no C:\ drive, no D:\ drive. Everything -- your documents, your configurations, your hardware devices, even running processes -- is represented as a file somewhere under /. Understanding this structure helps you navigate test environments, find configuration files, and locate logs quickly.

Here is the standard Linux filesystem layout:

/                   Root of the filesystem
├── home/user/      Your home directory (~)
├── etc/            Configuration files
├── var/
│   ├── log/        Application and system logs
│   └── lib/        Variable data (databases, packages)
├── tmp/            Temporary files (cleared on reboot)
├── opt/            Optional/third-party software
├── usr/
│   ├── bin/        User-installed binaries
│   └── local/      Locally compiled software
├── proc/           Virtual filesystem (process and kernel info)
├── dev/            Device files
└── srv/            Service data (web servers, FTP)

Each directory has a specific purpose. Knowing what lives where means you never have to guess where to look when something goes wrong.