I am having trouble with string replacement in powershell. Please consider the following expression:

```
"replaceTarget: %rep" -replace '%rep','$_'

```

I expect the result of this expression to be: 

```
replaceTarget: $_

```

but instead, it is 

```
replaceTarget: replaceTarget: $rep

```

I assume it is because the replacement string `'$_'` has some other meaning in the `replace` function.

How can I escape the input string so that `$_` can be passed in without being evaluated?