This chapter explains Introduction to Linux file system – Directory tree, Common Directories, special Directories, Absolute and relative paths.
The Linux File system
● The Linux file system has a tree like structure.
● The tree like structure is also referred to as the Directory tree
● When we draw the Linux file system on a paper , we see a tree like structure developing. That’s why it is called the directory tree.
● A folder is a location that stores multiple files
● Windows users usually use the word folder instead of a directory, however , in Linux terminology we always say a directory instead of a folder.
The Directory Tree
Here are some facts about the directory tree
● Each directory (or file) has exactly one parent
● The first directory (top most) in our directory tree is called the root directory .It is represented by a forward slash /
● The root directory contains files and sub directories, which contain more files and sub directories and so on.
Visualizing the file system
bin opt home tmp var ls pwd chrome earth john david temporary files log files music documents
/ The root directory ,
Where everything begins
This directory contains system configuration files
This directory contains the commands and utilities that you on a daily basis (All the users have access to it)
This directory contains programs that performs vital system tasks (Network management , Disk partitioning).Only the superuser has access to these programs.
Each user is given a directory under the home directory .A user can store anything in his home directory Ex:Music files,Pictures, …etc
This directory contains optional commercial software products that are not installed by default on the system (Ex: Google Earth)
This directory contains temporary files created by various programs. Generally cleared on reboot
Contains variable data (Ex: databases, spool files, user mail, etc. are located here. )
Two special Directories
● Under each directory , we have two special directories (1) The current directory represented as . (2) The parent directory represented as ..
● and so one dot refers to the current directory and two dots refers to the parent (Previous) directory.
Absolute and relative paths
● An absolute path begins with the root directory and follows the directory tree branch by branch until the path to the desired directory or file is completed. ● Example /home/john/documents/phone.txt is the absolute path of the file phone.txt Notice we use a / to separate between directories.
● A relative path starts from the current working directory. Example if our current working directory is john then ./documents/phone.txt is relative path of the file phone.txt
● You can omit the ./ and so documents/phone.txt also works