how to set display environment variable in linux code example

Example 1: show env in bash

#show all variable
printenv

#result one variable
echo $LOCALAPPDATA

Example 2: print environment variables linux

ENV_VAR="hello world"
printenv ENV_VAR

Example 3: linux set environment variable

# Linux - Bash 

# syntax 
# export *<variable-name>=*<variable-value>;

# example 
export ORACLE_SID='sales_database';