The easiest way to install the AWS CLI is using pip, it is a package manager for Python that provides an easy way to install, upgrade, and remove Python packages and their dependencies.

Install Python pip

CentOS :

sudo yum update -y
sudo yum install -y python-pip

Ubuntu :

sudo apt-get update -y
sudo apt-get install -y python-pip

Install AWS CLI using pip

pip install awscli --upgrade --user

–upgrade option tells pip to upgrade any requirements that are already installed.
–user option tells pip to install the program to a subdirectory of your user directory to avoid modifying libraries used by your operating system.

Add the executable path to your PATH variable: ~/.local/bin

export PATH=$PATH:~/.local/bin

Load the profile into your current session

source ~/.bash_profile

Verify that the AWS CLI installed correctly by running aws --version.

aws --version
aws-cli/1.16.19 Python/2.7.5 Linux/3.10.0-862.11.6.el7.x86_64  botocore/1.12.9

Configure AWS CLI

To access aws services using cli, we need to provide the access key and secret key along with a default region. This can be done using a subcommand provided by aws cli.

$ aws configure
AWS Access Key ID [None]: XXXXXXXXXXXXXXXXXXXX
AWS Secret Access Key [None]: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Default region name [None]: us-east-1
Default output format [None]: json

 I have used us-east-1 as default region and default output format is JSON. We can format the output as text and table formats as well.

aws configure command creates two configuration files located under .aws in user home directory.

ls ~/.aws/
config credentials

cat config 
[default]
output = json
region = us-east-1

cat credentials 
[default]
aws_access_key_id = XXXXXXXXXXXXXXXXXXXX
aws_secret_access_key = XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Verify if AWS CLI configuration

 Describe your regions

aws ec2 describe-regions
{
    "Regions": [
        {
            "Endpoint": "ec2.ap-south-1.amazonaws.com", 
            "RegionName": "ap-south-1"
        }, 
        {
            "Endpoint": "ec2.eu-west-3.amazonaws.com", 
            "RegionName": "eu-west-3"
        }, 
        {
            "Endpoint": "ec2.eu-west-2.amazonaws.com",
            "RegionName": "eu-west-2"
        }, 
        .....
        .....
        {   "Endpoint": "ec2.us-west-2.amazonaws.com", 
            "RegionName": "us-west-2" 
        } 
    ] 
}