UNIX for Beginners Questions & Answers

str="hello                       world. How are    you?"

if [[ $str == "hello[[:blank:]]world"* ]]; then
  echo "found"
else
  echo "not found"
fi

	shopt -s extglob
	temp=$(echo "${str//+([[:blank:]])/ }")
	if [[ $temp == "hello world"* ]]; then
		echo "found"
	fi

if [[ $(echo $str) == "hello world"* ]];

if [[ $str =~ "^hello[[:blank:]]*world" ]];

if [[ "$str" =~ ^"hello"[[:blank:]]+"world" ]];

if [[ "$str" =~ ^hello[[:blank:]]+world ]];

if [[ "$str" =~ ^hello[[:blank:]]+world.*\?$ ]];