In Linux, everything is a file.

SHIFT + ALT + T              # opens Terminal
CTRL + ALT + SHIFT + K       # computer shutdown (custom shortcut)

• /bin binaries
  • executable files (you can call them from terminal)
  • binary (ready to run, not readable for humans)
  • essential (a lot of system needed programs)
• /boot boot files
  • linux kernel (/boot/vmlinuz)
  • initial RAM disk image
  • boot loader (GRUB -> /boot/grub/grub.conf)
• /dev device nodes
  • all devices represented here as files
  • /dev/sda1 (sda -> name of disk)
  • usb devices / cpu / etc...
• /etc configuration files
  • system-wide configuration files
  • some shell scripts
  • all files are human readable
• /home users folders
  • each user has its own user-folder here
  • private data, pictures, videos etc...
• /lib libraries
  • libraries required by the programs in /bin folder
  • (library is a set of functions that are shared between programs)
• /lost+found recovered files
  • only exists when using ext4 file system (most linux distros use it)
  • recovery folder used by the ext4 file system
  • seperate folder for every ext4 partition
  • empty unless something happens (used for recovery)
• /media automatic mount point
  • automatic mounting of removable media such as USB drives, CD-ROM etc.
  • when properly setup usb drives should appear here!
  • mounting = accessing
• /mnt manual mount point
  • similar to /media folder, but its usually used for manual mounting
• /opt optional software
  • not essential
  • often used to install commercial programs (dropbox etc.)
• /proc kernel files
  • virtual file-system for the linux kernel
  • not touched by a user
• /root root home
  • do not mix with /
  • the same as your user home directory but its for the root account!
• /run early temp
  • recently introduced
  • tempoirary file-system
  • used early in system boot (before other temp folder become availible!)
• /sbin system binaries
  • binaries
  • essential
  • run by the super user
• /srv service data
  • service files installed on your system
  • for example a http webserver
• /tmp temporary files
  • temporary files
  • this directory is usually cleaned on reboot
• /usr user binaries
  • the largest folder after /home
  • contains all programs used by a regular user (thousands of programs)
  • /usr/bin binaries of programs installed by your distro
  • /usr/lib libraries used by the binaries
  • /usr/share/doc documentation files for programs installed on system
• /var variable files
  • files that change all the time
  • /var/log stores log files (that monitors processes)