are they collinear?
I think you can probably do it manually by drawing a new line (in a new layer), and hide the old layer.
I think new methods to be helpful:
1, create bounding box of selected entities;
2, zoom by selected;
trovo.alessandro.ta@gmail.com wrote
I have to merge multiple lines into one, how can I do? the problem is that the laser cutting machine reading lots of small lines continues to attach and detach and it takes a long time, would solve the problem if I could to merge them into a single