I've got a file with a bunch of long lines. I'd like to grab every group between two patterns and print them to a new file, one match per line. I could manage to do this with Python, but I'd prefer using just command line tools for this task. If there is no end pattern, I'd like to grab everything 'till the end of the line.
input: xxSTART relevanttext xxEND something else xxSTART even more relevant output: relevanttext even more relevant