I have an annoying problem with konsole: when I copy text from konsole and paste it into something else, the lines are very long - as long as the width of the konsole window, it seems. But not always, which means I can't even assume that I always have to strip the whitespace off the end. Is there a way to avoid this problem?

In the Profile settings, under Mouse, there is an option to Trim trailing spaces. Otherwise it will copy exactly what you see selected. (well, testing it out, it's only adding the padding spaces to the end of the command line, while other lines don't get extra spaces added; however I did verify that the Trim trailing spaces option works for getting rid of those padding spaces at the end of the command line)