How to remove extra spaces in bash?

Question

How to remove extra spaces in variable `HEAD`? ``` HEAD=" how to remove extra spaces " ``` Result: ``` how to remove extra spaces ```

Accepted Answer

Try this:

```
echo "$HEAD" | tr -s " "
```

or maybe you want to save it in a variable:

```
NEWHEAD=$(echo "$HEAD" | tr -s " ")
```

Update

To remove leading and trailing whitespaces, do this:

```
NEWHEAD=$(echo "$HEAD" | tr -s " ")
NEWHEAD=${NEWHEAD%% }
NEWHEAD=${NEWHEAD## }
```

Solution