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7/23/2019 Topic 1 - Intro to Linux
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Introduction to Linux
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t oduct o to u
nstructors info
Instructor : NGUYEN PHUONG QUAN
Mobi : 0972.259.260
Email : [email protected]
Com : SHB
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Linux Professional Institute Certification
Junior Level Administration (LPIC-1) Work at the command line.
Perform basic maintenance tasks.
Install and configure a workstation
Advanced Level Administration (LPIC-2) Administer a small to medium-sized site containing
Microsoft and Linux servers.
Supervise assistants.
Advise upper manangement.
Senior Level Administration (LPIC-3)
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Histoy of LINUX, UNIX
1983: GNU
1985: GPL
1991: Linux
1994: Redhat
2001: Linux 2.4Linus Torvald Tux
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LINUX VS UNIX
Linux Unix
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Linux Installation
2. Linux Boot Process
1. Linux Installation
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Linux Installation
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File System Overview
Linux filesystem is a single tree with the /directory as its root directory.
You create the single tree view of the
filesystem by mounting the filesystems ondifferent devices at a point in the tree called
a mount point
Files or subdirectories that were already inmountpoint are no longer visible when new
filesystem is mounted there
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Filesystem Hierarchy Standard
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Partitions
Three types of partition on hard
drives:primary,logical, andextended
Thepartition table is located in themaster boot
record (MBR) of a disk
When more than 4 partitions are required, one oftheprimarypartitions must become an extended
partition
Linux numbers primary or extended partitions as 1through 4
If logical partitions are defined, they are
numbered starting at 5
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Recommended Partition Scheme
Mountpoint Size Description
/ 4GB or
more
Contains all directories not
present on other filesystems
swap 2 x RAM size used to support virtual memory
/boot 100MB Contains the Linux kernel and
boot files
/home 200MB per
user
Default location for user home
directories
/var 2GB or
more
Contains log files and spools
/tmp As much as
possible
Holds temporary files created by
programs
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Linux Installation Process
1. Boot from an installation source
2. Select installation mode
3. Select language and keyboard layout
4. Partition the hard disk
5. Select boot loader options
6. Configure network interfaces
7. Select time zone
8. Set roots password
9. Customize software packages to be installed
10. Start the installation
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Linux Boot Process
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Boot Loader PrinciplesLinux
1. Boot process begins with the BIOS2. BIOS load the MBR (primary boot loadercode)
3. Primary boot loadereither:
A. Loads the boot sector from bootable primary partition
(secondary boot loader), which continues the process byloading an OS kernel. DOS and Windows use this.
B. Load the OS kernel directly (bypass the secondary bootloader). Linux supports this.
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Linux boot loader
LILO (LInuxLOader) or GRUB (GRandUnifiedBootloader)
Can be installed in MBR or boot sector of primarybootable partition.
Trouble comes if your system is dual-boot (Windows+ Linux) Install LILO/GRUB in MBR: can be wiped out if you re-installing
Windows
Install LILO/GRUB in boot sector: remain intact, although Windowsmight configure the system to bypass it.
This partition must be a primary partion
You must you FDISK to re-mark the Linux partition as the boot partitoin
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LILO vs GRUB
LILO GRUB
Configuration file /etc/lilo.conf /boot/grub/grub.confor
/boot/grub/menu.lst
Support booting from a
network
No Yes
Command to install lilo grub-install
Require re-install after
changing configuration file
Yes No
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Example of grub.conf
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Example of lilo.conf
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Linux boot process
System booting process:
1. System is power on, CPU runs the BIOS
2. BIOS load the primary boot loader in MBR
3. Primary boot loader load secondary loader in boot sector
4. Boot loader load the Linux kernel
5. Linux kernel initializing devices, mounting root partitionand run /sbin/init
6. /sbin/init read /etc/inittab to determine what otherprogram to run based on default runlevel
Extracting information about the boot process:dmesg | lessless /var/log/messages
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Runlevel
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The System Startup Scripts
Runlevel specific scripts are stored in /etc/rc.d/rc?.dor /etc/init.d/rc?.d
All scriptss name are begin with S or K Example: S10network, K35smb
Scripts are actually symbolic links to main scripts in/etc/rc.d or /etc/init.d/
When entering a runlevel, rc:
pass start parameter to S* scripts
pass stop parameter to K* scripts
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Managing Runlevel
View default runlevel
grep :initdefault: /etc/inittabView current runlevel:runlevel
Change to another runlevel:
telinit runlevelList the services and their applicable runlevels:chkconfig --list [servicename]
Modify the runlevels in which a services run
chkconfig --level runlevels servicename {on|off|reset} Example:chkconfig --level 345 nfs-common on
Text-based menu driven tools:ntsysv
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Exercise
1. Login as root in graphical mode
2. Learn your current runlevel with runlevel
3. If your system reports its in runlevel 5, type telinit 3 to switchto runlevel 3. See whats difference?
4. Return to your orginal runlevel with telinit 5
5. Edit /etc/inittab and change the default runlevel to 3
6. Reboot the computer by typing reboot now or shutdown -rnow
7. Login as root again and type runlevel to verify that yourerunning in the runlevel you specified in step 5
8. Edit /etc/inittab to restore it to its original state
9. Type telinit 6. This enters runlevel 6, which reboot the system.
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Q A
Thank You