Command not found Error (stderr) while comparing string in Bash Script

Question

Problem is to read one character from the user (this may be 'Y', 'y', 'N', 'n'). If the character is Y or y display YES. If the character is N or n display NO.

Original Problem

Here's my code:

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

It throws an Error (stderr)

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

Answer 1

Leave space before ] and after [ in if statement.. if [ "$option"="y" ] || [ "$option"="Y" ]

Answer 2

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

Answer 3

You can use this in BASH:

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