I have quite a few saws around the workshop. Most of them are of the people-powered kind, but I do have a couple of ones with plugs on the ends as well.
I was given a jigsaw a few birthdays ago and it’s become one of my go-to tools. I bought some good quality aftermarket blades and by swapping these in to suit the task at hand I find it handles straight and curved work well.
You can cut a straight line with a jigsaw without a guide, but with a fast cutting blade even a small deviation can result in a couple of millimeters drift in your cut.
To make it easier to get accurate straight cuts I made myself a guide. I started with a couple of bits of angle aluminium It’s cheap, easy to work and very stable, but you could use wood for the rails as well if you wanted to. I cut it to length with a hacksaw and used a file against the edge of my shooting board to square the ends.
I cut a pair of pine pieces to use as fences (say that a few times quickly!) and marked the center point. I used the center point mark on the jigsaw base to center it then fitted the rails snugly to the sides of the jigsaw and marked it up.
I used an automatic center punch to mark the screw holes on both pieces.
I then screwed it all together, and used a coping saw and rasp to round the ends of the fences, just to make it look nicer.
Here it is finished with the jigsaw sitting in it so you can see how it works in action. You put the fence furthest away from you against the edge of the board you want to cut and clamp it in place, then put the jigsaw in so that the blade is in front of the fence closest to you and start cutting. It would work better with only one fence but with the length of it the second one helps keep the rails square.