How to set up and use AWS CLI

Here’s a detailed guide on how to use the AWS CLI to manage your AWS services from the command line.

Step 1: Install AWS CLI

On Windows

Download the AWS CLI MSI installer from the AWS website.
Run the MSI installer and follow the instructions.

On macOS

Using Homebrew:
```
 brew install awscli
```
Or using pip:
```
 pip install awscli
```

On Linux

Using the package manager (Ubuntu/Debian):

 sudo apt-get update
 sudo apt-get install awscli

Or using pip:
```
 pip install awscli
```

Step 2: Configure AWS CLI

After installing, configure the AWS CLI with your credentials:

aws configure

You will be prompted to enter the following information:

AWS Access Key ID: (Your access key ID)
AWS Secret Access Key: (Your secret access key)
Default region name: (Your preferred region, e.g., us-west-2)
Default output format: (Your preferred output format, e.g., json)

You can also edit the configuration manually in ~/.aws/config file.

Step 3: Using AWS CLI

Here are some common AWS CLI commands. They are seperated into services.

1. EC2

An EC2 (instance) is virtual computer, located in AWS data center.

List all instances:
```
  aws ec2 describe-instances
```

Start an instance:

  aws ec2 start-instances --instance-ids i-1234567890abcdef0

Stop an instance:

  aws ec2 stop-instances --instance-ids i-1234567890abcdef0

Launch a new instance:

  aws ec2 run-instances --image-id ami-0abcdef1234567890 --count 1 --instance-type t2.micro --key-name MyKeyPair --security-group-ids sg-12345678 --subnet-id subnet-12345678

2. S3

List all buckets:
```
  aws s3 ls
```
Create a bucket:
```
  aws s3 mb s3://my-bucket
```
Upload a file:
```
  aws s3 cp myfile.txt s3://my-bucket/
```

Download a file:

  aws s3 cp s3://my-bucket/myfile.txt myfile.txt

3. IAM

List users:
```
  aws iam list-users
```

Create a user:

  aws iam create-user --user-name my-user

Attach a policy to a user:

  aws iam attach-user-policy --user-name my-user --policy-arn arn:aws:iam::aws:policy/AmazonS3FullAccess

Step 4: Automation with Scripts

You can create scripts to automate AWS tasks. Here’s an example of a script to stop all instances:

#!/bin/bash
instances=$(aws ec2 describe-instances --query 'Reservations[*].Instances[*].InstanceId' --output text)

for instance in $instances; do
  aws ec2 stop-instances --instance-ids $instance
done

Save this script as stop_all_instances.sh, then run it:

bash stop_all_instances.sh

Step 5: Documentation and Support

AWS CLI has extensive documentation. You can refer to the official documentation here.

Using the AWS CLI allows you to manage AWS services efficiently and automate many tasks, improving your workflow significantly.