Linux Fundamentals
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Linux Fundamentals

Paul Cobbaut

2015-05-24

Table of Contents

I. introduction to Linux

1. Linux history

1969
1980s
1990s
2015

2. distributions

Red Hat
Ubuntu
Debian
Other
Which to choose ?

3. licensing

about software licenses
public domain software and freeware
Free Software or Open Source Software
GNU General Public License
using GPLv3 software
BSD license
other licenses
combination of software licenses

II. installing Linux

4. installing Debian 8

Debian
Downloading
virtualbox networking
setting the hostname
adding a static ip address
Debian package management

5. installing CentOS 7

download a CentOS 7 image

Virtualbox

CentOS 7 installing

CentOS 7 first logon

setting the hostname

Virtualbox network interface

configuring the network

adding one static ip address

package management

logon from Linux and MacOSX

logon from MS Windows

6. getting Linux at home

download a Linux CD image
download Virtualbox
create a virtual machine
attach the CD image
install Linux

III. first steps on the command line

7. man pages

man $command
man $configfile
man $daemon
man -k (apropos)
whatis
whereis
man sections
man $section $file
man man
mandb

8. working with directories

pwd

cd

cd ~
cd ..
cd -

absolute and relative paths

path completion

ls

ls -a
ls -l
ls -lh

mkdir

mkdir -p

rmdir

rmdir -p

practice: working with directories

solution: working with directories

9. working with files

all files are case sensitive

everything is a file

file

touch

create an empty file
touch -t

rm

remove forever
rm -i
rm -rf

cp

copy one file
copy to another directory
cp -r
copy multiple files to directory
cp -i

mv

rename files with mv
rename directories with mv
mv -i

rename

about rename
rename on Debian/Ubuntu
rename on CentOS/RHEL/Fedora

practice: working with files

solution: working with files

10. working with file contents

head

tail

cat

concatenate
create files
custom end marker
copy files

tac

more and less

strings

practice: file contents

solution: file contents

11. the Linux file tree

filesystem hierarchy standard

man hier

the root directory /

binary directories

/bin
other /bin directories
/sbin
/lib
/opt

configuration directories

/boot
/etc

data directories

/home
/root
/srv
/media
/mnt
/tmp

in memory directories

/dev
/proc conversation with the kernel
/sys Linux 2.6 hot plugging

/usr Unix System Resources

/usr/bin
/usr/include
/usr/lib
/usr/local
/usr/share
/usr/src

/var variable data

/var/log
/var/log/messages
/var/cache
/var/spool
/var/lib
/var/...

practice: file system tree

solution: file system tree

IV. shell expansion

12. commands and arguments

arguments

white space removal

external or builtin commands ?
type
running external commands
which

aliases

create an alias
abbreviate commands
default options
viewing aliases
unalias

displaying shell expansion

practice: commands and arguments

solution: commands and arguments

13. control operators

; semicolon

& ampersand

$? dollar question mark

&& double ampersand

|| double vertical bar

combining && and ||

# pound sign

\ escaping special characters

end of line backslash

practice: control operators

solution: control operators

14. shell variables

$ dollar sign
case sensitive
creating variables
quotes
set
unset
$PS1
$PATH
env
export
delineate variables
unbound variables
practice: shell variables
solution: shell variables

15. shell embedding and options

shell embedding

backticks
backticks or single quotes

shell options

practice: shell embedding

solution: shell embedding

16. shell history

repeating the last command
repeating other commands
history
!n
Ctrl-r
$HISTSIZE
$HISTFILE
$HISTFILESIZE
prevent recording a command
(optional)regular expressions
(optional) Korn shell history
practice: shell history
solution: shell history

17. file globbing

* asterisk
? question mark
[] square brackets
a-z and 0-9 ranges
$LANG and square brackets
preventing file globbing
practice: shell globbing
solution: shell globbing

V. pipes and commands

18. I/O redirection

stdin, stdout, and stderr

output redirection

> stdout
output file is erased
noclobber
overruling noclobber
>> append

error redirection

2> stderr
2>&1

output redirection and pipes

joining stdout and stderr

input redirection

< stdin
<< here document
<<< here string

confusing redirection

quick file clear

practice: input/output redirection

solution: input/output redirection

who | wc
who | cut | sort
grep | cut

practice: filters

solution: filters

20. basic Unix tools

find
locate
date
cal
sleep
time
gzip - gunzip
zcat - zmore
bzip2 - bunzip2
bzcat - bzmore
practice: basic Unix tools
solution: basic Unix tools

21. regular expressions

regex versions

grep

print lines matching a pattern
concatenating characters
one or the other
one or more
match the end of a string
match the start of a string
separating words
grep features
preventing shell expansion of a regex

rename

the rename command
perl
well known syntax
a global replace
case insensitive replace
renaming extensions

sed

stream editor
interactive editor
simple back referencing
back referencing
a dot for any character
multiple back referencing
white space
optional occurrence
exactly n times
between n and m times

bash history

VI. vi

22. Introduction to vi

command mode and insert mode
start typing (a A i I o O)
replace and delete a character (r x X)
undo and repeat (u .)
cut, copy and paste a line (dd yy p P)
cut, copy and paste lines (3dd 2yy)
start and end of a line (0 or ^ and $)
join two lines (J) and more
words (w b)
save (or not) and exit (:w :q :q! )
Searching (/ ?)
replace all ( :1,$ s/foo/bar/g )
reading files (:r :r !cmd)
text buffers
multiple files
abbreviations
key mappings
setting options
practice: vi(m)
solution: vi(m)

VII. scripting

23. scripting introduction

prerequisites
hello world
she-bang
comment
variables
sourcing a script
troubleshooting a script
prevent setuid root spoofing
practice: introduction to scripting
solution: introduction to scripting

24. scripting loops

test [ ]
if then else
if then elif
for loop
while loop
until loop
practice: scripting tests and loops
solution: scripting tests and loops

25. scripting parameters

script parameters
shift through parameters
runtime input
sourcing a config file
get script options with getopts
get shell options with shopt
practice: parameters and options
solution: parameters and options

26. more scripting

eval
(( ))
let
case
shell functions
practice : more scripting
solution : more scripting

VIII. local user management

27. introduction to users

whoami
who
who am i
w
id
su to another user
su to root
su as root
su - $username
su -
run a program as another user
visudo
sudo su -
sudo logging
practice: introduction to users
solution: introduction to users

28. user management

user management
/etc/passwd
root
useradd
/etc/default/useradd
userdel
usermod
creating home directories
/etc/skel/
deleting home directories
login shell
chsh
practice: user management
solution: user management

29. user passwords

passwd
shadow file
encryption with passwd
encryption with openssl
encryption with crypt
/etc/login.defs
chage
disabling a password
editing local files
practice: user passwords
solution: user passwords

30. user profiles

system profile
~/.bash_profile
~/.bash_login
~/.profile
~/.bashrc
~/.bash_logout
Debian overview
RHEL5 overview
practice: user profiles
solution: user profiles

31. groups

groupadd
group file
groups
usermod
groupmod
groupdel
gpasswd
newgrp
vigr
practice: groups
solution: groups

IX. file security

32. standard file permissions

file ownership

user owner and group owner
listing user accounts
chgrp
chown

list of special files

permissions

rwx
three sets of rwx
permission examples
setting permissions (chmod)
setting octal permissions
umask
mkdir -m
cp -p

practice: standard file permissions

solution: standard file permissions

33. advanced file permissions

sticky bit on directory
setgid bit on directory
setgid and setuid on regular files
setuid on sudo
practice: sticky, setuid and setgid bits
solution: sticky, setuid and setgid bits

34. access control lists

acl in /etc/fstab
getfacl
setfacl
remove an acl entry
remove the complete acl
the acl mask
eiciel

35. file links

inodes

inode contents
inode table
inode number
inode and file contents

about directories

a directory is a table
. and ..

hard links

creating hard links
finding hard links

A. keyboard settings

about keyboard layout
X Keyboard Layout
shell keyboard layout

B. hardware

buses

about buses
/proc/bus
/usr/sbin/lsusb
/var/lib/usbutils/usb.ids
/usr/sbin/lspci

interrupts

about interrupts
/proc/interrupts
dmesg

io ports

about io ports
/proc/ioports

dma

about dma
/proc/dma

C. License

Index

List of Tables

2.1. choosing a Linux distro
4.1. Debian releases
22.1. getting to command mode
22.2. switch to insert mode
22.3. replace and delete
22.4. undo and repeat
22.5. cut, copy and paste a line
22.6. cut, copy and paste lines
22.7. start and end of line
22.8. join two lines
22.9. words
22.10. save and exit vi
22.11. searching
22.12. replace
22.13. read files and input
22.14. text buffers
22.15. multiple files
22.16. abbreviations
30.1. Debian User Environment
30.2. Red Hat User Environment
32.1. Unix special files
32.2. standard Unix file permissions
32.3. Unix file permissions position
32.4. Octal permissions