The FHS (Filesystem Hierarchy Standard) is followed.
- most basic progs reside here
- ls, cat, etc reside here
- used by the system admin
- bootloaders reside here
- don't touch unless absolutely sure
- legacy mounting point
- home for devices and their driver files
- keyboard, webcam, hard disk, etc reside here
- sda is a hard disk and the partitions can be sda1, sda2, etc... (as everything in linux is a file)
- storage for all system-wide configurations like apt
- store for applications to keep their files
- these files are reqd by the binaries in bin, sbin and other places
- for external mounted devices like USBs, floppies, etc
- use mnt for manual mounting & leave media for the OS to manage
- manually installed software reside here
- user can install their software here
- contains sudo files (like dev) that have info on sys processes & resources
- mapped as per PID (process ID)
- root user's home folder
- not like the typical user's home folder & it does not reside in the home dir
- files can be stored here, but they need root permissions to be accessed
- different distros use it differently
- tempfs (temporary file system)
- it runs in RAM (so everything in this folder is gone when the system is rebooted or shut down...)
- snap package store
- mainly used by ubuntu
- service data store
- if you run a server (eg: FTP server), then the files to be accessed by the external user are to be stored here
- to interact with kernel
- created every time the system boots up
- temp file store
- ususlly empty every time system boots
- user application space
- application to be used by user are installed here as opposed to bin or sbin
- applications here are considered to be non-essential for basic system op
- files & dirs expected to grow in size
- eg: log, crash, spool (temp printer queue), etc
- each user has their own folder
- store for personal files & docs
- each user can access only their own home folder unless they have admin permissions
- has hidden folders like .cache (files that are used too often like thumbnails, etc), .config, .local