在Bash脚本中比较字符串时未找到命令错误（stderr）

Question

问题是从用户读取一个字符（可能是'Y', 'y', 'N', 'n'）。如果字符为Y或y则显示YES。如果字符为N或n则显示NO。

Original Problem

这是我的代码：

read option
if ["$option"=="y"] || ["$option"=="Y"]
then
    echo "YES"
else
    echo "NO"
fi

抛出错误 (stderr)

solution.sh: line 2: [Y=y]: command not found
solution.sh: line 2: [Y=Y]: command not found

Answer 1

read option
if [ "$option" == "y" ] || [ "$option" == "Y" ]
then
echo "YES"
elif [ "$option" == "n" ] || [ "$option" == "N" ]   
then
echo "NO"
else
echo "?"
fi

Answer 2

在if ]之前和[之后留出空格。if [ "$option"="y" ] || [ "$option"="Y" ]

Answer 3

你可以在BASH中使用它：

[[ "$option" == [Yy] ]] && echo "YES" || echo "NO"