install go / golang on ubuntu

install_go_ubuntu.sh

#! /bin/bash

# --------------------------------------------
# Go installization script for ubuntu.
# Tested on 16.04
# 
# What it does:
#   1. Install go for the system
#   2. create GOPATH for the current user
# 
# Instructions:
#   1. Modify configurations 
#   2. sudo ./install_go.sh
# --------------------------------------------

# configurations
GO_ROOT_PREFIX=/usr/local
GOPATH=/home/$SUDO_USER/go
GO_VER=1.8
GO_VER_FILE_CHECKSUM=53ab94104ee3923e228a2cb2116e5e462ad3ebaeea06ff04463479d7f12d27ca

# check user privilege
if [[ "$EUID" -ne 0 ]]; then
    echo "Error: please run with sudo."
    exit 
fi

# Download go binaries
GO_FILE=go$GO_VER.linux-amd64.tar.gz
wget -nc https://storage.googleapis.com/golang/$GO_FILE
checksum=`sha256sum $GO_FILE | awk '{print $1}'`
if [[ $checksum != $GO_VER_FILE_CHECKSUM ]]; then
    echo "CHECKSUM doesn't match!"
    echo "expecting: $GO_VER_FILE_CHECKSUM"
    echo "got      : $checksum"
    exit 1
fi

echo "extracting go tools to $GO_ROOT_PREFIX/go"
tar -C $GO_ROOT_PREFIX -xzf $GO_FILE

# Setup paths and variables 
if [[ $GO_ROOT_PREFIX != /usr/local ]]; then
    echo "export GOROOT=$GO_ROOT_PREFIX/go" > /etc/profile.d/go.sh
    echo 'export PATH=$PATH:'$GOROOT/bin >> /etc/profile.d/go.sh
    echo "GOROOT is set to: $GOROOT"
else 
    echo 'export PATH=$PATH:'$GO_ROOT_PREFIX/go/bin > /etc/profile.d/go.sh
fi 
chmod +x /etc/profile.d/go.sh
source /etc/profile.d/go.sh

# Setup GOPATH
mkdir -p $GOPATH/src
mkdir $GOPATH/bin
mkdir $GOPATH/pkg
export GOPATH=$GOPATH
export PATH=$PATH:$GOPATH/bin
echo "export GOPATH=$GOPATH" >> $HOME/.bashrc
echo 'export PATH=$PATH:$GOPATH/bin' >> $HOME/.bashrc

# Test go installization
mkdir $GOPATH/src/hello
echo 'package main

import "fmt"

func main() {
    fmt.Printf("hello, world\n")
}' > $GOPATH/src/hello/hello.go

cd $GOPATH/src/hello
go build
rc=$?
if [[ $rc == 0 ]]; then 
    echo "Go Installization Success"
else
    echo "Go Installization Failed, exit code: $rc"
fi
rm -rf $GOPATH/src/hello

chown -R $SUDO_USER: $GOPATH
chown $SUDO_USER: /home/$SUDO_USER/.wget-hsts