Simple inspector for Docker container IP address (shell script)

docker-container-ip.sh

#!/bin/bash
# Simple inspector for Docker container IP address
# https://gist.github.com/mugifly/3bb1c54b48764340eda8

print_help () {
    echo -e "USAGE: docker-container-ip.sh KEYWORD\n"
    echo "KEYWORD: A keyword string for target container."
    echo "    e.g. dokku.mysql.foobar"
    echo -e "\n[Example usecases]"
    echo "  Connect to MySQL database in container:"
    echo "    1. Run the command: $ docker-container-ip.sh mysql"
    echo "    2. You got the ip address -- e.g. 172.17.0.1"
    echo "    3. Connect to it: $ mysql -h 172.17.0.1 -u foo -p"
}

keyword=$1
if [ $# -ne 1 ]; then
    echo -e "Please set a keyword as argument! such as container name.\n"
    print_help
    exit 255
fi

container_ids=$(docker ps | grep $keyword | grep -o -e '^\S*')

for id in $container_ids
do
    name=$(docker inspect --format="{{ .Name }}" $id)
    ip=$(docker inspect --format="{{ .NetworkSettings.IPAddress }}" $id)
    echo "${id} ${name} = ${ip}"
done

exit 0