ssh-keygen -R がメンドくさい

.profile

function rmkey(){
    TARGET_HOST=$1
    if [ -z "$TARGET_HOST" ]; then
        echo "must hostname or ipaddr"
        return 1
    fi
    if [[ $TARGET_HOST =~ [0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3} ]]; then
        ssh-keygen -R $TARGET_HOST
    elif [[ $TARGET_HOST =~ [a-zA-Z0-9]{3,20} ]]; then
        ssh-keygen -R $TARGET_HOST
    else
        echo "Fales"
    fi
    return 0
}