CentOS7 Docker install script

centos-docker-install.sh

#!/bin/sh

#
# Common
#
print() {
	reset='\033[0m'

	case $2 in
		info)
			color='\033[0;34m';;
		success)
			color='\033[0;32m';;
		error)
			color='\033[0;31m';;
		warning)
			color='\033[0;33m';;
	esac

	echo -e "${color}${1}${reset}"
}

error() {
	print "$1" error
	exit 1
}

#
# Docker
#
echo "CentOS Docker installer/updater"
echo "Installing/Updating docker"
if which docker > /dev/null;
then
	print "Docker already installed - skipping ..." success
else
	print "Installing docker ..." info
	yum install -y docker
	if [ $? -ne 0 ]
	then
		error "Error while installing docker"
	fi
fi

#
# Download
#
print "Downloading binaries and support files ..." info
if [ -f 'docker-latest.tgz' ]
then
	print "-> binaries found locally!" success
else
	print "-> downloading binaries ..." info
	wget https://get.docker.com/builds/Linux/x86_64/docker-latest.tgz
fi

if [ -f 'docker.socket' ]
then
	print "-> docker.socket found locally!" success
else
	print "-> downloading docker.sock ..." info
	wget https://raw.githubusercontent.com/docker/docker/master/contrib/init/systemd/docker.socket
fi

if [ -f 'docker.service' ]
then
	print "-> docker.service found locally!" success
else
	print "-> downloading docker.service ..." info
	wget https://raw.githubusercontent.com/docker/docker/master/contrib/init/systemd/docker.service
fi
print "Binaries downloaded successfully" success

#
# Install
#
echo
print "Installing binaries ..." info
tar -zxf docker-latest.tgz
cp ./usr/local/bin/docker /usr/bin/
cp -u docker.* /etc/systemd/system
rm -rf ./usr
print "Binaries installed successfully" success

print "Docker installed successfully" success
print "Use 'service docker restart' to start the docker daemon" success