UNIX for Dummies Questions & Answers

if [$inputPin !=  [[0-9]\{3,3\]}]

if [[ "$STR" =~ ^[0-9][0-9][0-9]$ ]]
then
    echo "Three digits"
fi

 case "$STR" in
[0-9][0-9][0-9])
        echo "Three digits"
        ;;
*)
        ;;
esac

if [[ ! $inputPin =~ "[0-9]{3,3}" ]]

if [[ "$STR" =~ ^[0-9][0-9][0-9]$ ]]
then
    echo "Three digits"
fi

if [[ ! $inputPin =~ "[0-9]{3,3}" ]]

if [[ $STR == {3}([[:digit:]]) ]]
then
    print "Three digits"
fi

if [[ $zz =~ ^[0-9]{3,3}$ ]]
then
    echo "Three digits"
fi