# USE1.3 UNIX File System Tree

The UNIX file system is organized hierarchically according to the Filesystem Hierarchy Standard.

UNIX follows the philosophy that everything is a file. Directories are indicated with a "/" separator and start from the root directory "/" and different devices are linked to this tree.

Files and directories can be referred to either using absolute or relative file names.

Typically, several elementary programs are pre-installed and allow access and manipulation of files and directories.

## Requirements

## Learning objectives

  * Describe the organization of a hierarchical file system.
  * Explain the basic UNIX permission model and metadata of files.
  * Describe the Filesystem Hierarchy Standard and the relevance of the directories:
    * etc
    * home
    * opt
    * lib and /usr/lib
    * bin and /usr/bin
    * sbin and /usr/sbin
    * tmp
  * Utilize tools to navigate and traverse the file system:
    * ls (-R, -l)
    * cd
    * pushd/popd
    * stat
  * Use tools to read files:
    * cat
    * head/tail
    * less/more
    * cmp
  * Utilize tools to manipulate the file system:
    * mkdir/rmdir
    * touch
    * cp/mv
    * ln
  * Utilize tools to identify and manipulate permissions:
    * chmod
    * chown/chgrp

# Subskills