Long text substitution

[teambelair]

Hi All,

I have a long text field where the user basically writes down a list of tasks. Each line is a task
When the user completes a task, he simply adds “**” at the beginning of the task.

On an another hidden long text field I would like to keep only the remaining tasks (basically a copy of the source text field without any lines that start with “**”

Basically, I am trying to erase text that is between “**” (included) and a line break.

Any idea on how I can achieve that?

Thanks!