Linux is an open source operating system created by Linus Torvalds that manages computer hardware and software resources. The document provides an introduction to Linux and teaches how to navigate and manipulate files and directories using commands like ls, cd, touch, and rm in the command line interface. It also covers finding, editing, archiving, and permissions of files as well as processes and getting help.

1. Linux:
A Getting Started presentation
by: Nap Ramirez
email: napramirez@gmail.com

2. INTRODUCTION
What is Linux?
Linux is an operating system* created
by Linus Torvalds, with the help of
developers around the world.
* An operating system is a special set of programs that
manages the hardware and software resources of a
computer.

3. INTRODUCTION
Why Linux?
● It's free!
● It is Open Source Software.
● It is reliable.
● Perks include:
✔ no viruses
✔ no need to restart all the time
✔ no registration/activation hassles
✔ unlimited support
✔ a large pool of applications for your preference

4. GETTING USED TO...
The File System
In Linux, files and directories are
organized in a hierarchical tree-like
structure.

5. GETTING USED TO...
The File System (continued)

6. GETTING USED TO...
The File System (continued)
● File system entries can be files or
directories
e.g. file: hello.txt
directory: src/
● Entries are case-sensitive
e.g. 'hello.txt' is NOT equal to 'HELLO.TXT'
● Hidden entries start with a dot '.'
e.g. .bash_profile is a hidden file

7. GETTING USED TO...
The File System (continued)
● In Linux, files and directories are bound
to ownership and permissions
● File system entries are owned by users
● Users may have the following permissions:
✔ read
✔ write
✔ execute/entry

8. GETTING USED TO...
The File System (continued)
NOTE: The displayed
Properties Dialog
may vary in
different window
themes.

9. INTRODUCTION TO...
The Shell
● The shell is an environment and a
means of communication with the
operating system's kernel
● Either a GUI or CLI
● Usually pertains
to the CLI

10. GETTING TO KNOW...
The CLI
The command line interface (CLI) is a
program that takes text input from the
user that may, in turn, be used as
directives to the operating system.

11. LEARNING...
File System Navigation
● ls – list contents of directory
✔ -l list in detail
✔ -a list all, including hidden files
✔ -F list, use indicators (dir: /, executable: *, link: @)
● cd – change directory
✔ ~ (user's home directory)
✔ - (previously visited directory)
✔ . (current directory)
✔ .. (parent directory)
✔ / (root directory)
● pwd – print working directory

12. LEARNING...
Creating Entries
● touch – mainly used to change
timestamps of entries, it can be used
to create files if specified files do
not exist
● mkdir – create directory
✔ -p create parent directories, if non-existent

13. LEARNING...
Copying/Moving Entries
● cp – copy entry
✔ -r copy recursively
● mv – move entry

14. LEARNING...
Deleting Entries
● rm – delete file
✔ -r delete recursively
● rmdir – delete empty directory

15. LEARNING...
Output Pagers
Pagers suppress the output of a
command. This is useful if the output
doesn't fit the screen. Pagers can be
used by piping* the output of commands
into them.
● more
● less
* Piping is the passing of output of one command into another,
it is denoted by the pipe character |.

16. LEARNING...
Output Commands
These commands usually display output
too big to fit in the screen. They are
commonly used with pagers.
● echo – displays the specified text
● cat – displays the content of the
specified file
● tail – displays the last part of a
file
● head – displays the first part of a
file

17. LEARNING...
Editing Text Files
Many text editors exist in every
installation. The most popular are:
● vi, vim
● emacs
● joe
● pico, nano

18. LEARNING...
Setting Permissions
● chmod <mode> <entry> [-r]
✔ Recall that permissions are set for the
owner/user (u), group (g), others (o)
✔ <mode> is the permissions set for any of
the owner/user, group, others
e.g `chmod ug+rw .bash_profile`
`chmod o-rwx .bash_profile`
● Use `ls -l` to verify the changes

19. LEARNING...
Finding Files
● which – used to find executables
● locate – find indexed entries
● find – find files in the file system
`find <path> -name <file>`

20. LEARNING...
Archiving Files
● gzip/gunzip
`gzip <file>`, `gunzip <file>.gz`
● tar
`tar cf <file>.tar <path>`
`tar xf <file>.tar`
● zip/unzip
`zip [-r] <file> <path>`
`unzip <file>`

21. LEARNING...
Output Redirection
While piping allows control of output into
another program's input, redirection
forwards the output to a file.
● > - output is saved into a file
e.g. `echo “hello” > hello.txt`
(hello.txt contains “hello”)
● >> - output is appended into a file
e.g. `echo “hello again” >> hello.txt`
(“hello again” is added)

22. LEARNING...
Process Control
● & - appending '&' to a command will
bring the process to the background and
returns the user to the prompt
● ps (process snapshot) – list processes
● fg (foreground)
● bg (background)
● kill
● top

23. WHEN IN DOUBT...
Help
● man – manual pages about commands
e.g. `man <command>`
● apropos – search the man page names
e.g. `apropos <command>`
● info – information on commands
e.g. `info <command>`
● -h or --help – used as arguments to a
command
e.g. `ls --help`

24. MORE LEARNING...
Extras
● sudo – execute as superuser
e.g. `sudo chown nap:nap hello.txt`
● df – display disk space usage
● -h – human-readable
● du – display file space usage
● -sh – human-readable summary

25. MORE LEARNING...
Extras
● env – list all environment variables
● export – set variable in the environment
e.g. `export BASH_HOME=~`
● set/unset – pick environment variables
● `set BASH_HOME=”asdf”`
● `unset BASH_HOME`

26. Let's put it to the test!
Exercise
Identify the ff commands:
unzip, strip, touch, finger, grep, mount, fsck,
more, yes, fsck, fsck, fsck, umount, sleep

27. THE END...
Thanks!
Please mail me your feedback!
----------------------------
Nap Ramirez
napramirez@gmail.com

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