Unix File System Chapter 6.1 – 6.7

2 Unix file system Home directory – A directory set aside for your personal use – The starting point when you log in Working directory – Whatever directory you are currently in Initially, the working directory is the home directory The cd command is used to change the working directory

3 Typical Unix file system root (/) bindevtmpusrvarusers classescsfacstfacstaffspool mailugradmsphdcs (all users’ mail)

4 Typical Directories bin: Software for the shell and most common Unix commands dev: Short for devices, holds the software necessary to operate peripherals such as printers and terminals etc: Contains various administrative files such as lists of user names and passwords

5 Typical Directories usr/users: Contains the home directories of users tmp: A directory used to hold temporary files var: Files that contain information that varies frequently; most commonly, mail directories

6 File and Directory Names Valid names can be made up of: – Uppercase letters (A to Z) – Lower case letters (a to z) – Numbers (0 to 9) – period (.), underscore (_), commas (,) Should not contain spaces or the following: – & * \ | [ ] { } $ ( ) # ? ‘ “ / ; ^ ! ~ % – You should also avoid naming files or directories with Unix commands

7 Absolute Pathnames To use a file in Unix, all you need is its name To access a file in another directory, you need to know its pathname A pathname is an address that shows the file’s position in the file system Absolute path names give a files location in relation to the top of the file system structure

8 Example Directory Structure root (/) binetcvartmp continentsoceans Bats marsupials bandicoot kangaroowombat dev homeusr jack jill opossum wombat

9 Absolute Pathnames All absolute path names begin with a ‘/’ Also called full path names Use the ~ as a shortcut for the full path to your home directory

10 Relative path names Usually you are interested in a files location relative to where you currently are in the system A relative pathnames start at the working directory rather than the root Use ‘..’ to refer to the parent of the current directory

11 Example Directory Structure root (/) binetcvartmp continentsoceans Bats marsupials bandicoot kangaroowombat dev homeusr jack jill opossum wombat