I’ve started to do a significant amount of work on a new iPad, and Workflow is the best $2 I think I’ve spent so far. It has the potential to build an almost unlimited number of workflows which are scripts that can do most anything. I think its most important feature is to act as a lubricant to ease over the rough spots inherent in iOS. I’d best describe it as a Swiss Army knife that you build for yourself.

After having the Workflow app for several days, I had built a few utilities mostly just to see what was possible. But this morning I found a use that really filled a hole in my mobile workflow: merging PDF files.

The guts of the Merge PDFs workflow.

This is one of those things that you don’t realize you need until you really need it. Of course there’s plenty of apps (mostly of questionable quality) that will take two PDFs and combine them. But all of them seem to suffer from the same limitation: the need to import the files and then work on them in the app’s own file storage area.

What I wanted was to take two files that were already in iCloud and merge them, and then save the result right back to iCloud. After a quick search I found that the trick to do this was to use the Workflow module Add to Variable when selecting the second PDF. Once that was sorted, it was a simple matter to build the workflow.

Now if I want to add a cover page to a story I can save it from any app that produces PDFs (like Pages), and then put it at the front of a PDF produced from Ulysses that contains the document body. This also works for cover sheets produced by Ulysses too. Sometimes it’s easier to have a separate export styles for the cover and body. Now I can easily merge them without having to resort to using the laptop.

If you’re interested in trying this out, I’ve uploaded it to the Workflow gallery here.