Installing nodeJS for a single user

Install-NodeJS.sh

#!/bin/bash

# File: Install-NodeJS.sh

# Desc: A script to install NodeJS in a subdirectory named node_v
#       on a server.

# License: [MIT](https://mit-license.org/)

# Usage:
#        Make a directory to run the script
#          $ mkdir node_workspaces
#        Upload the script to the new directory
#        Make the script executable.
#          $ chmod 755 Install-NodeJS.sh
#        Then run it
#          $ ./Install-NodeJS.sh
# = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

# User changeable variables

# Script runner, you will need to manually check to see which
# version is the latest for long term support (LTS) by visiting the
# nodejs.org website then paste the correct link for your system here
linkToNodeJS="http://nodejs.org/dist/v6.10.0/node-v6.10.0-linux-x64.tar.gz"

# on the server commandline type 'uname -a' to see the long version
# of server info, enter one server bus type in bus, for example:
   bus="x86_64" # or
#  bus="i386"   # or

# = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
# Make no user changes below here ...
  # command reference:
  #  http://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html
fileToExtract=${linkToNodeJS##*/}

#echo $HOME
workingDir=`pwd`
scriptName=`basename "$0"` # script name

clear

# - - - - - - - - - - - - - - - - - - - - - - - -
# Begin Definition of Functions
# - - - - - - - - - - - - - - - - - - - - - - - -
continueInstall () {
	# function receives no inputs, however expects
	# yes/no response from the user
	#   no:  exits from script
	#   yes: allows script to proceed
	proceed="" #initialize

	while [[ "$proceed" == "" ]]; do
	  printf "Okay to proceed type[yes/no]:"
	  # expect non blank input
	  read proceed

	  case $proceed in
		n* )
	  	      printf "\nAt your request the script exited without doing the install.\n"
		      exit 1 #just end it all right now
			;;
		y* )
	          printf "\nProceeding with the installation.\n\n"
	          break #get out of the the while loop
			;;
	    * )
	  	      printf "\nInvalid entry: $proceed; Usage: yes / no . "
			;;
	  esac

	  proceed="" #clear it and try again
    done # / while
	} # / continueInstall



myDownLoader () {
	# Expect:
	#        the full url to download from
	#        optional target file name
	# usage:
	#       myDownLoader $sourceURL $targetFileName
	# - - - - - - - - - - - - - - - - - - - - - - - -
	# download
	local sourceURL="$1"
	local targetFileName="$2"
	printf "\npreparing to download file $targetFileName\n"
	printf "from $sourceURL\n\n"

	which wget # does it exist?
	local wgetStatus="$?" # the exit status

	which curl # does it exist?
	local curlStatus=$? # exit status

	debugSwitch=0 # 0 is real downloads
	              # 1 is debugging (no download)
	if [[ "$debugSwitch" == "1" ]]; then
		echo "debugging mode, not really downloading"
	fi

	if [[ "$debugSwitch" == "0" ]]; then
		downloadStatus=""
		if [[ "$wgetStatus" == "0" ]]; then
			  echo "trying wget command"
		      wget $sourceURL
		      downloadStatus=$?
			elif [[ "$curlStatus" == "0" ]]; then
		      echo "trying curl command"
		      # curl -o targetFileName sourceURL
		      curl -o $targetFileName $sourceURL
		      downloadStatus=$?
		    else
		      echo "Did not find wget or curl in the PATH, therefore"
		      echo "could not download the requested file."
		fi #endif downloader
	fi # endif debug switch
	return $downloadStatus
} # / end function myDownLoader


# - - - - - - - - - - - - - - - - - - - - - - - -
# / End Definition of Functions
# - - - - - - - - - - - - - - - - - - - - - - - -

printf "\n\nHello, $USER \n\n"
echo "You are running script $scriptName and are preparing"
echo "to install NodeJS on `hostname` in a subdirectory"
echo "named node_v in the current working directory:"
printf "   $workingDir \n\n"

continueInstall


# reference: http://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html
#http://stackoverflow.com/questions/1371261/get-current-directory-name-without-full-path-in-bash-script
currentDirectoryName=${PWD##*/} # remove everything up to and including the last slash

if [[ "$currentDirectoryName" == "node_v" ]]; then
	echo "This script is already in a directory named node_v"
	echo "the directory structure will look like node_v/node_v"
	continueInstall
fi


# system check
myServer="`uname -a`" # the long version of server info
# user defined 'bus' at top of program for example
#    bus="x86_64" # or
#    bus="i386"   # or
# install only on a system identified with bus
if [[ $myServer =~ ($bus) ]]; then
    # continue with the installation
    echo "On system with $bus."
else
	echo "Expecting $bus type system, could not confirm type match."
    echo "uname -a:"
    echo "$myServer"
	echo "Exiting without installing NodeJS"
	exit 1
fi
# / end system check


echo "Making and switching into directory node_v"
mkdir node_v
cd node_v
workingDir=`pwd`
echo $workingDir

#myDownLoader $sourceURL $targetFileName
myDownLoader $linkToNodeJS $fileToExtract


# - - - - - - - - - - - - - - - - - - - - - - - -
# shasum check the downloaded file
# curl https://nodejs.org/dist/v4.4.5/SHASUMS256.txt -o SHASUMS256.txt
theComparisonFileName="SHASUMS256.txt" # by definition from nodejs website
getShasumFrom="$(dirname $linkToNodeJS)"
urlCheckSum="$getShasumFrom/$theComparisonFileName"

# curl $urlCheckSum -o $theComparisonFileName
myDownLoader $urlCheckSum $theComparisonFileName

# compare the listed sums to the calculated sums of the local files
#shasum -a 256 -c SHASUMS256.txt 2>&1 | grep OK
sumResult=$(shasum -a 256 -c SHASUMS256.txt 2>&1 | grep OK)

if [[ "$sumResult" =~ "OK" ]]; then
    echo "SHASUMS256: $sumResult"
    echo "download was okay, sums list no longer needed"
    rm SHASUMS256.txt
else
	echo "SHASUMS256 does NOT match, NOT okay to proceed"
	echo "Try changing into node_v directory, then run the commmand"
	echo "shasum -a 256 -c SHASUMS256.txt 2>&1 | grep OK"
fi
# / end of shasum check
# - - - - - - - - - - - - - - - - - - - - - - - -


# - - - - - - - - - - - - - - - - - - - - - - - -
echo "Untarring file $fileToExtract"
echo "Into working directory $workingDir"
tar -xvzf $fileToExtract --directory=$workingDir --strip-components=1
# if exit code was okay then delete the zip file
if [[ "$?" == "0" ]]; then
	printf "\ntar exited with no erros\n"
	printf "removing the compressed file $fileToExtract\n\n"
	rm -rf $fileToExtract
fi

printf "\n\nA A directory listing:"
ls
# / end of the untarring
# - - - - - - - - - - - - - - - - - - - - - - - -

# - - - - - - - - - - - - - - - - - - - - - - - -
# create symbolic links for node and npm in the PATH
printf "\n\ncreating symbolic links for node and npm\n\n"

cd ~ # ET go home
mkdir bin # a directory that is probably in the users PATH
cd bin
ln -s $workingDir/bin/node node
ln -s $workingDir/bin/npm npm
cd $workingDir
nodeVersion=$(node -v) # test it
nodeExitResult=$?
npmVersion=$(npm -v)
npmExitResult=$?
if [[ ("$nodeExitResult" == "0") && ("$npmExitResult" == "0")]]; then
  	printf "\n\nNode version $nodeVersion and npm version $npmVersion are installed\n"
  	printf "in $workingDir\n\n"
  else
  	printf "\n\nThe install may not have completed correctly.\n"
  	printf "The commands 'node -v' and 'npm -v' should return version numbers\n\n"
fi
# / end creating symbolic links
# - - - - - - - - - - - - - - - - - - - - - - - -


# remove the functions from bash
unset continueInstall
unset myDownLoader