This document provides an overview of the Linux file system including: 1. It defines the main directories and contents according to the Filesystem Hierarchy Standard (FHS) with the root directory being "/" and possible multiple partitions and filesystems. 2. It describes the different types of files like ordinary files, directories, and special files as well as file permissions for reading, writing, and executing files and directories. 3. It explains how to change file permissions using the chmod command and navigate the file system using commands like pwd, cd, and ls including examples of using options, wildcards and navigation.

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2. Index
Introduction
File System Hierarchy Standard
Types of file
Acces Mode of files and directory
Changing Permission
Navigation Command
Linux File System

3. Introduction
All data in Linux organized into files.
All files are organized into directories.
These directories are organized into a tree-like
structure called the file system.
Linux file system also enables you to group files
into directories, which is similar to folder you
create in windows explorer
Linux File System

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 Defines the main directories and their contents in most
Linux-based systems
 There is not any drive C:, D:, …
 All directories are under “/”
 “/” is the root directory
 It is possible
 to have multiple partitions
 to multiple filesystems
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6. Filesystem Hierarchy Standard
(continued)…
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7. cont….
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8. cont….
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9. Types of file
-> Ordinary Files:
An ordinary file is a file on the system that contains data, text, or
program instructions.
-> Directories:
Directories store both special and ordinary files. For users
familiar with Windows or Mac OS, UNIX directories are equivalent
to folders.
Linux File System

10. Types of file
-> Special Files:
Some special files provide access to hardware such as hard
drives, CD-ROM drives, modems, and Ethernet adapters. Other
special files are similar to aliases or shortcuts and enable you to
access a single file using different names.
Linux File System

11. File Access Mode
Read:
 Grants the capability to read ie. view the contents of the file.
Write:
 Grants the capability to modify, or remove the content of the file.
Execute:
 User with execute permissions can run a file as a program.
Linux File System

12. Directory Access Modes
Read:
Access to a directory means that the user can read the
contents. The user can look at the filenames inside the
directory.
Write:
Access means that the user can add or delete files to the
contents of the directory.
Execute:
A user must have execute access to the bin directory in
order to execute ls or cd command.
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13. Interpreting the Mode
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14. Changing Permission
 chmod (change mode) command: Change mode (permissions) of files or
directories.
 Permissions stored in a file’s.
 New files given rw-rw-rw- permissions by default
Linux File System

15. Changing Permission
Linux File System

16. Navigating the File System
• Pwd (Present Working Directory)
• cd
• ls
Linux File System

17. Using the pwd Command
 pwd stands for Print Working Directory.
 pwd is a Linux / Unix command which prints the current working
directory.
 pwd prints the full pathname of the current working directory.
Syntax
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pwd [OPTION]...

18. Using the pwd Command
-P, --physical Print the Physical Directory Path Without any Sysmbolic
Linux File System
Link.
--help Display a help message.
--version Display version information.

19. Using the pwd Command
Examples:
$ pwd
/home/IT
and the computer prints out /home/IT, that means that the directory the
user is currently in is /home/IT.
In the following example, the user is located in the directory
/usr/local/bin, uses the command pwd, uses the command cd .. to move
back to the parent directory and then uses pwd again:
Example:
Linux File System
$ pwd
/usr/local/bin
$ cd ..
$ pwd
/usr/local

20. Using the cd Command
 The Linux cd command stands for change directory.
 It is the primary command for moving between directories on a
Unix/Linux filesystem.
 Syntex:
Linux File System
cd [directory]
 Here directory is the name of the directory where you wish to go.
.

21. Examples of cd command
 Change working directory to /abc/xyz
pwd
/home/IT
cd /abc/xyz
pwd
/abc/xyz
 Change working directory to user’s home directory
pwd
/etc/BCA
cd ~
or
cd
pwd
/home/IT
 Change working directory to parent directory.
cd ..
Linux File System

22. Examples of cd command
 Change working directory to parents parent directory or two levels up in
the directory structure.
cd ../..
 Using wildcards
cd /v*
The * wildcard characters can be interpreted as "any number of
any character", so the Linux system expands the /v* that typed into
/var
 Change the working directory to /var/ftp without mentioning ftp fully.
cd /var/ft?
This will change the directory to /var/ftp
Linux File System

23. Pushd command
 Use pushd command to change the directory. This is similar
to cd command.
 It saves the current working in memory .
Ex. pushd /var/ftp/pub
Linux File System

24. Using the ls Command
 ls is a Linux shell command that lists directory contents and
Files.
 ls syntax
$ ls [options] [file|dir]
# ls
0001.Pcap Desktop Downloads index.html install.log.syslog Pictures
Templates anaconda-ks.cfg Documents fbcmd_update.php install.log
Music Public Videos
Linux File System

25. Using the ls Command
ls -a list all files including hidden file starting with '.'
ls -d list directories - with ' */'
ls -F It differenciate files and directory.
ls -i list file's inode index number
ls -l list with long format - show permissions
ls -la list long format including hidden files
ls -lh list long format with readable file size
Linux File System

26. Using the ls Command
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l
ls -ls list with long format with file size
ls -r list in reverse order
ls -R list recursively directory tree
ls -s list file size
ls -S sort by file size
ls -t sort by time & date
ls -X sort by extension name

27. Using the ls Command
# ls -a
. .bashrc Documents .gconfd install .log .nautilus .pulse-cookie ..
.cache Downloads .gnome2 install .log.syslog .netstat.swp .recently-used.
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l
xbel 0001 .pcap .config .elinks
# ls -F
0001.Pcap Desktop/ Downloads/ index.html install.log.syslog
Pictures/ Templates/ anaconda-ks.cfg Documents/ fbcmd_update.php
install.log Music/
$ ls -1
bin
boot
//Display One File Per Line Using ls -1
cdrom
dev

28. Using the ls Command
Linux File System
l
$ ls / /*List root directory*/
$ ls .. List /*parent directory*/
$ ls ~ /*List user's home directory*/
$ ls * /*List all subdirectories*/
$ ls *.txt /*List only text files with wildcard*/
$ ls > out.txt /*ls redirection to output file*/

29. Using the ls Command
# ls -lS
total 176
-rw-r--r--. 1 root root 48867 Jul 31 02:17 install.log
-rw-r--r--. 1 root root 46701 Jul 31 09:58 index.html
-rw-r--r--. 1 root root 21262 Aug 12 12:42 fbcmd_update.php
-rw-r--r--. 1 root root 11439 Jul 31 02:13 install.log.syslog
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Desktop
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Documents
drwxr-xr-x. 4 root root 4096 Aug 16 02:55 Downloads
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Music
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Pictures
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Public
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Templates
drwxr-xr-x. 2 root root 4096 Jul 31 02:48 Videos
-rw-------. 1 root root 1586 Jul 31 02:17 anaconda-ks.cfg
-rw-r--r--. 1 root root 683 Aug 19 09:59 0001.pcap
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30. Using the ls Command
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l
# ls -i
20112 0001.pcap 23610 Documents 23793 index.html 23611 Music
23597 Templates 23564 anaconda-ks.cfg 23595 Downloads 22 install.log
23612 Pictures 23613 Videos 23594 Desktop 23585 fbcmd_update.php
35 install.log.syslog

31. That’s All About Linux File
System Navigation
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32. Thank You
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