PDF Renamer allows to change the file name of PDF files.
PDF Renamer is designed to be launched indirectly via the "Open in ..." dialog of another application. Usually, it will be started from Safari's preview of a recently downloaded PDF. This PDF can then be renamed and forwarded to a third-party application.
If PDF Renamer is launched directly, i.e. without a document, then it will run in demo mode. In this mode, two sample documents are provided, but it is not possible to open custom files. Note that this is no artificial limitation of the free PDF Renamer application, but a rigorous constraint imposed by the iOS operating system.
PDF documents feature a file name and, additionally, an optional internal title. While in most cases the former is very short, avoids special characters and spaces, and contains the suffix ".pdf" (e.g. "tax_2011.pdf"), the latter, if available, usually consists of the full document title without suffix (such as "Tax declaration 2011").
Some versions of the iBooks application give the the internal full title preference over the short file name when it is dealing with PDF documents.
The Safari browser is able to download PDFs from the internet, but the version of Safari in iOS 4 discards the original file names and generates new ones. The one in iOS 5 and 6 keeps the original file name when handing over a PDF to another application.
If you pass a PDF that has no internal title definition from Safari (iOS 4) to iBooks (versions earlier than v1.5), you end up with an ugly document name such as "QL-8GVvMPPk.pdf", which cannot be changed and syncs to your Mac/PC using that name.
If you have already imported the document into iBooks, you must delete it there first. Then forward it from Safari to PDF Renamer, type in a better name, press the "Preview and forward" button to open a document preview, from which you can pass it on again to iBooks, now using the new name. Alternatively, you can use the "Forward without preview" button to avoid the document preview.
Of course, PDF Renamer also works with any other two applications, not just Safari and iBooks. In this case, a renaming feature might already be built into the source or target application.
Using the buttons "without title" and "with title", which are only visible if no PDF was supplied on application launch, you can import two sample PDF files (one with and one without an internal title definition) directly into PDF Renamer. These files were specifically prepared for test purposes. You can rename and forward them to (e.g.) iBooks. The sample files themselves contain explanations about what result is to be expected under which circumstances.