file system
/bin
- binary files for terminal commands and core utilities
/boot
- GRUB and files needed for boot - may be located on a separate partition
/cdrom
- optical drive might be mounted here
/dev
- devices - hard drives are mounted here, and sometimes other devices
/etc
- configuration files, e.g. for SSH or installed applications
/home
- where user folders are stored (~)
/lib
, /lib32
, /lib64
- libraries - files used for installed applications; somewhat comparable to Program Files on Windows
/media
- where external devices like flash drives might be mounted
/mnt
- another place external devices might be mounted, as well as remote folders
/opt
- “optional software for the system” ??
/proc
- processes - stuff used for the kernel to communicate with the running processes (?)
/root
- user account for the root
user; its equivalent of home
/run
- a place where flash drives etc might automatically mount
/sbin
- similar to bin
but for commands that can only be run by root or superuser
/snap
- where downloaded snap apps live
/tmp
- temporary files, usually deleted when system shuts down
/usr
- user - utilities shared between users
/var
- variable - system logs and other data, e.g. apache uses it as a default storage location
swapfile
- the system swap (extra memory for when RAM is maxed out or whatever)