传递参数时不带双引号时抛出错误

Question

#!/usr/bin/env bash
#myscript.sh



if [[ "$1" == "" ]]
then
    echo "Hello, "
elif ! [[ "$1" =~ "*[a-z]*[A-z]" ]]
then
    echo "Usage: error_handling.sh $1"
elif [[ "$1" != "" ]]
then
    echo "Hello, $1"
else
    echo "Usage: error_handling.sh $1"
fi

上述脚本的目的是当脚本像这样运行时抛出（自定义）错误：

./myscript.sh Alice

即显示错误如下：

"Usage: error_handling.sh Alice"

但如果同样的脚本像这样运行：

./myscript.sh "Alice"

它应该显示：

Hello, Alice

但是它会针对这两种情况抛出自定义错误语句。

如何解决此问题？