checkLinuxDistro.sh

#!/bin/bash

declare -a releases=("debian" "ubuntu" "centos")
shopt -s nullglob
shopt -s nocasematch 

# Case 1
#dmesg | grep debian, ubuntu etc. 
#uname -a | grep
#lsb_release -a | grep

for i in "${releases[@]}"
do
    dmesg | grep  "$i"
	#if previous command succeeded
	if [ $? -eq 0 ]; then
	echo "$i" "- found in dmesg"
	fi

	uname -a | grep  "$i"
	if [ $? -eq 0 ]; then
	echo "$i" "- found in uname -a"
	fi

	cat /etc/issue | grep "$i"  # same as lsb_release -a 
	if [ $? -eq 0 ]; then
	echo "$i" "- found in /etc/issue"
	fi

done

# Case 2

arr=(/etc/*release)

for i in "${arr[@]}"
do
   release=$(grep ID_LIKE $i | cut -d'=' -f2)

   if [ -n "$release" ]; then
	echo "Found ID_LIKE in" "$i"

	case "$release" in
		"debian" | "ubuntu")
		echo "apt-get";  #check if vm-tools installed
	    ;;
		"centos")
		echo "yum";
		;;
		*)
		echo $release
		;;
	esac
   fi #if [ $? -eq 0 ]
done #for i in "${arr[@]}"