how to create an environment variable linux code example

Example 1: linux set environment

# syntax 
# setenv SHELL *

# example
setenv SHELL /usr/bin/bash

Example 2: set environment variable linux

vi ~/.bash_profile

Example 3: linux set environment variable

# Linux - Bash 

# syntax 
# export *=*;

# example 
export ORACLE_SID='sales_database';

Example 4: add environment variable linux

source ~/.bash_profile