Proxy Configuration

Permanent Proxy Settings

vi /etc/profile
export http_proxy='http://username:password@proxy_ip:port'
export https_proxy='http://username:password@proxy_ip:port'
source /etc/profile

Temporary Proxy Settings

export http_proxy=http://username:password@proxy_ip:port/
export ftp_proxy=http://username:password@proxy_ip:port/

YUM Proxy Configuration

vi /etc/yum.conf
proxy_username=proxy_user
proxy_password=proxy_pass

Git Proxy Configuration

git config --global https.proxy http://username:password@proxy_ip:port
git config --global http.proxy http://username:password@proxy_ip:port

Linux Fundamentals

Linux consists of kernel (handling CPU, memory, file, network, and I/O scheduling) and system aplpications.

Virtual Machines

Virtual machines emulate computer hardware and run real operating systems.

Directory Structure

Linux uses a single-rooted tree structure without drive letters.

Essential Commands

File Operations

ls -lah               # List files with details
mkdir -p dir/subdir   # Create nested directories
chmod 755 file.txt    # Change permissions
chown user:group file # Change ownership

Process Management

ps -ef | grep process # Find processes
kill -9 PID          # Force kill process
top                  # Monitor system resources

Software Installation

MySQL Installation

rpm --import https://repo.mysql.com/RPM-GPG-KEY-mysql-2022
rpm -Uvh http://repo.mysql.com/mysql57-community-release-el7-7.noarch.rpm
yum -y install mysql-community-server
systemctl start mysqld

Tomcat Insatllation

wget https://dlcdn.apache.org/tomcat/tomcat-10/v10.1.8/bin/apache-tomcat-10.1.8.tar.gz
tar -zxvf apache-tomcat-10.1.8.tar.gz -C /opt
/opt/apache-tomcat-10.1.8/bin/startup.sh

Nginx Installation

yum install -y yum-utils
vi /etc/yum.repos.d/nginx.repo
yum install -y nginx
systemctl start nginx

RabbitMQ Installation

rpm --import https://github.com/rabbitmq/signing-keys/releases/download/2.0/rabbitmq-release-signing-key.asc
yum install -y erlang rabbitmq-server
systemctl start rabbitmq-server
rabbitmq-plugins enable rabbitmq_management

Redis Installation

yum install -y epel-release
yum install -y redis
systemctl start redis
redis-cli

Elasticsearch Installation

rpm --import https://artifacts.elastic.co/GPG-KEY-elasticsearch
yum install -y elasticsearch
systemctl start elasticsearch