Manage AWS EC2 instances with a single-line command

mldev.sh

#!/bin/sh

ProgName=$(basename $0)
instance_ids=i-05806fb95d65fffff
region=us-west-2

sub_help(){
    echo "Usage: $ProgName <subcommand> [options]\n"
    echo "Subcommands:"
    echo "    start     Start mldev instances"
    echo "    stop      Stop mldev instances"
    echo "    describe  Describe mldev instances"
    echo "    modify    Modify mldev instance types"
    echo ""
    echo "For help with each subcommand run:"
    echo "$ProgName <subcommand> -h|--help"
    echo ""
}

sub_start(){
    echo "Running 'start' command."
    aws ec2 start-instances --instance-ids $instance_ids --region $region
}

sub_stop(){
    echo "Running 'stop' command."
    aws ec2 stop-instances --instance-ids $instance_ids --region $region
}

sub_describe(){
    echo "Running 'describe' command."
    aws ec2 describe-instances --instance-ids $instance_ids --region $region --query "Reservations[*].Instances[*].{PublicIP:PublicIpAddress,Name:Tags[?Key=='Name']|[0].Value,Status:State.Name,InstanceID:InstanceId,Instancetype:InstanceType}"
}

sub_modify(){
    instance_type=$1
    echo "Running 'modify $instance_type' command."
    aws ec2 modify-instance-attribute --instance-id $instance_ids --instance-type "{\"Value\": \"$instance_type\"}"
}

subcommand=$1
case $subcommand in
    "" | "-h" | "--help")
        sub_help
        ;;
    *)
        shift
        sub_${subcommand} $@
        if [ $? = 127 ]; then
            echo "Error: '$subcommand' is not a known subcommand." >&2
            echo "       Run '$ProgName --help' for a list of known subcommands." >&2
            exit 1
        fi
        ;;
esac