System AdministratorResponsible for?

• Install OS • Network Configuration• Security Configuration• Patching• Backup• Performance Management• Storage Management• User Management• TroubleShooting & Maintainance• Vendor Management Created by

http://linux.velocity-lab.net/

Who You Work with

Sys Admin

Network Team

Storage Admin

Backup Admin

Database AdminSecurity

Team

Application Team

Noc/Help Desks

Facilities

Vendors

Created by

http://linux.velocity-lab.net/

Operating System [OS]

OS

Unix

AIX(IBM) HPUX Oracle Solaris Linux

Redhat Suse Debain Ubuntu Mint

Windows

Created by

Environment

• Development or sandboxing

Development Environment

Created by

Severity Level

Severity 1 (urgent) :

Severity 2(High):

Severity 3(Medium):

Severity 4(Low):

Created by

What is Operating System

• A software program designed to act as an interface between a hardware and the user.

• It controls the hardware, manages system resources and supervises interaction between the system and its users.

OS

User

Shell

kernel

Hardware

Linux Operating System

Kernel

Kernel

• Kernel : Core of the Unix OS. It interacts with the hardware. It is loaded into memory when the system is booted. Its functions are

- the kernel is responsible for memory management, process and task management, and disk management.

- The kernel connects the system hardware to the application software

Shell

• Simply put, the shell is a program that takes your commands from the keyboard and gives them to the operating system to perform. In the old days, it was the only user interface available on a Unix computer. Nowadays, we have graphical user interfaces (GUIs) in addition to command line interfaces (CLIs) such as the shell.

• On most Linux systems a program called bash (which stands for Bourne Again SHell, an enhanced version of the original Bourne shell program, sh, written by Steve Bourne) acts as the shell program. There are several additional shell programs available on a typical Linux system. These include: ksh, tcsh and zsh.

Shell

• Bourne Shell (sh) -- This shell does not have the interactive facilities provided by modern shells such as the C shell and Korn shell.

• C Shell (csh) -- It provides a C-like language with which to write shell scripts - hence its name.

• Korn Shell (ksh) -- It provides all the features of the C and TC shells together with a shell programming language similar to that of the original Bourne shell.

• Bash Shell(bash) -- Bash provides all the interactive features of the C shell (csh) and the Korn shell (ksh). Its programming language is compatible with the Bourne shell (sh).

PATH

• Absolute Path:-> An absolute path is defined as the specifying the location of a file or directory from the root directory(/). In other words we can say absolute path is a complete path from start of actual filesystem from / directory. Eg: /var/ftp/pub

• Relative Path:-> Relative path is defined as path related to the present working directory(pwd). Suppose I am located in /var/log and I want to change directory to /var/log/kernel. I can use relative path concept to change directory to kernel .Eg: pwd

/var/logcd kernel

UseFul commands

http://linuxcommand.org/lc3_learning_the_shell.php

FileSystem

Logical Volume 500MB Logical Volume 1GB

/dev/appvg Volume Group 20GB

Physical Partition pvcreate /dev/sdb1 Physical Partition pvcreate dev/sdb2

/dev/sdb Physical Hard Drive fdisk /dev/sdb 20 GB

/dev/sdb1 10 GB /dev/sdb2 10GB

vgcreate appvg /dev/sdb1 /dev/sdb2

Lvcreate –L 500 –n datalv appvg

mkfs.ext4 /dev/appvg/datalv

Lvcreate –L 1024 –n sharelv appvg

mkfs.ext4 /dev/appvg/sharelv

lvextend –L +500 /dev/appvg/datalv

free 18.5 GBresize2fs /dev/appvg/datalv

Logical Volume (pvcreate)Volume group (vgcreate)

Logical volume (lvcreate)

mount –t ext4 /dev/appvg/datalv /data mount –t ext4 /dev/appvg/sharelv /share

Mount point /data Mount point /share