Linux

1. Introduction
2. Installation
3. SQL Query in Shell Script
4. Basic commands


1. Introduction

Similar to DB Administrator and DB Developer we have Linux Administrator and Linux Developer. Here we deal with the concepts of Linux Developer. Unix, Linux, Windows, Mac all are operating systems.
Different peripherals: Input device; Output device (Monitor); Primary memory (RAM); Auxiliary memory (Hard disc); Controllers (8051 model); CPU (8086 model). We have to develop programs that can instructs the peripheral as per the architecture of the vendor. Lets assume we have developed one application using above hardware architecture. If another end user came to develop same application but with different hardware architecture like CPU is 8085 model then we have to write altogether new program. Change in hardware – change in program, was the earlier process. Now the invention of OS removed this problem. They developed one software that controls hardware so no need to talk to hardware directly.

→ Linux is basically same as Unix. They both have same features.
→ Unix has corporate support but Linux is developed by user contributions.
→ Linux is free open source OS based in Unix features and facilities.
→ We can consider Linux as full clone of Unix.

The basic entities of Linux are Kernel, Shell and Utilities.
→ Kernel acts as a bridge between hardware and software components. Application ⇔ Kernel ⇔ Hardware devices like CPU/ Memory/ Devices
→ Shell is an interface to communicate with OS. Shell ⇔ OS ⇔ Kernel ⇔ Hardware
We have four types of Shells. Bourne Shell (SH); C Shell (CSH); Bourne Again Shell (BASH); Korn Shell (KSH);
→ Utilities are nothing but commands


2. Installation

1. Base Machine — Base machine with Windows or MAC OS.
⇓⇑
2. Virtual Machine — Install Virtual Machine software. Ideally VM player will be used but not recommended for personal use. Its preferable to use Virtual box which is provided by Oracle. VM player should be used with high configurations, mostly in industries. Virtual box is of light weight and < 0.5 GB memory will be used. Resources from Base machine will be used by Virtual machine, making base machine slow in performance.
⇓⇑
3. Configure or deploy different virtual machines as per choice.

Steps:
1. Download Virtual box software
2. Download Extension pack
3. Download Developer days [Sand box from Oracle]
4. Install Virtual box software
5. Upload Developer days software into Virtual box.

Sandbox which is provided by Oracle has Linux, Oracle 11g and Java pre-configured.

Installation:
Type virtualbox in google >> Oracle VM Virtual box (virtualbox.org) >> Dont download the latest version (currently its 5.2) as it may have some bugs >> Left side go to downloads >> Look for ‘VirtualBox older builds’ >> Look for no longer supported >> Preferably install VirtualBox 4.3 >> Download ‘Windows hosts x86/AMD64’ under ‘VirtualBox 4.3.40 (released August 22nd 2016)’>> Download ‘Extension Pack All Platforms’ under ‘VirtualBox 4.3.40 (released August 22nd 2016)’ >> Save in some drive >> Here we are just trying to get Virtual Machine

Developer days (Sandbox — We can work on Linux, Java and Oracle) >> oracle.com >>  Trials and downloads >> More downloads >> Under ‘Servers and Storage Systems’, go to ‘VM VirtualBox’ >> Download

In Virtual Machine Virtual Box >> File >> Import >> Appliance >> Upload Sand Box >> Select Developer Day >> Open >> Next >> Modify name as Linux; Virtual disk image: Do not keep in c drive as it impacts performance. Do not change .vmdk extension >> Import >> Agree

In Virtual Machine Virtual Box >> Settings >> General >> Advanced tab >> Shared Clipboard: Bi-Directional >> Drag and drop: Bi-Directional >> System: Can increase memory upto green line in base memory. This can be altered based on base memory >> Shared folders >> Others >> e drive >> create new folder >> VB shared >> Select >> Ok >> Automount >> Ok>> Double click Linux >> Username root; Password: oracle >> For command line: Applications >> Accessories >> Terminals


3. SQL Query in Shell Script

#Start of V0.2
####################################################################
instance_name=$TWO_TASK
file_path=`sqlplus -s $username_password<< EOF
set head off
set feed off
set echo off
set line 999
 SELECT description
  FROM FND_LOOKUP_VALUES
 WHERE     1 = 1
       AND lookup_type = 'custom_lookup_type'
       AND enabled_flag = 'Y'
       AND meaning = '$instance_name';
 exit
EOF`

#Output of sql query value will be stored in file_path and to read this value use $file_path
L_OUTPUT_DIR=$file_path
L_SOURCE_FILE=$file_path/$file_name

#End of V0.2

4. Basic commands

clear screen: clear
present working directory: pwd
find files with partial name: find . -name "xx_loadapps*"
remove log files: rm *.log
remove debug files:rm *.debug
give 777 permissions: chmod 777 *.*