Question: I'm working on a site using a Jupiter 4 theme. Within the dashboard there are options to configure the header layout, but there is nothing there to add a background image to the header.

The stylesheet is located at themes/jupiter/stylesheet/css/styles.css. In it, I have tried putting a `background-image: url('/wp-content/uploads/2016/04/header-miami-beach-sign.png');` in different id definitions that start with #mk-header, but no image is displaying. The header background is just a solid white color.

I'm trying to turn **this:**

[![plain header](https://i.stack.imgur.com/Chyzd.png)](https://i.stack.imgur.com/Chyzd.png)

into **this:**

[![header with a feature background image](https://i.stack.imgur.com/V6ksO.png)](https://i.stack.imgur.com/V6ksO.png)

Answer: 
Instead of `!=`, you have to use `! $var =~ regex` to perform [regex comparisons](https://stackoverflow.com/a/21112809/1983854):

```
[[ $date =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]]
         ^^

```

So that your script can be like this:

```
date=""
while [[ ! $date =~ ^[0-9]{4}-[0-9]{2}-[0-9]{2}$ ]]; do
    echo "enter date (YYYY-MM-DD)"
    read $date
done

```
Why not convert the incorrect format to desired one using date program:

```
$ date -d "06/38/1992" +"%Y-%m-%d"
1992-06-28

```

You can also check for conversion failure by checking return value.

```
$ date -d "06/38/1992" +"%Y-%m-%d"
date: invalid date ‘06/38/1992’

$ [ -z $? ] || echo "Error, failed to parse date"

```