You can create new documents from existing PDF files by breaking the PDFs into smaller pieces or combining them with information from other PDFs.
As a document proceeds through its lifecycle, it can undergo many changes. It might be assembled from individual sections and then compiled into a larger report. Individual pages might be copied into a personal reference document. Sections might be replaced as new information becomes available. Some documents are agglomerations of smaller pieces, like an expense report with all of its lovely and easily lost receipts.
While it's easy to manipulate paper pages by hand, you must use a program to manipulate PDF pages. Adobe Acrobat can do this for you, but it is expensive. Other commercial products, such as pdfmeld from FyTek (http://www.fytek.com), also provide this basic functionality. The pdftk PDF toolkit [Hack #79] is a free software alternative.
In Acrobat 6, select File Create PDF From Multiple Files . . . . Click the Browse . . . button (Choose . . . on a Macintosh) to open a file selector. You can select multiple files at once. On Windows, you can select a variety of file types, including Microsoft Office documents. Arrange the files into the desired order and click OK.
To quickly combine two PDF documents using Acrobat 5, begin by opening the first PDF in Acrobat. In the Windows File Explorer, select the PDF you want to append, drag it over the PDF open in Acrobat, and then drop it. A dialog will open, asking where you want to insert the PDF. Select After Last Page and it will be appended to the first PDF.
If you have a folder of PDF files to combine and their order in the Windows File Explorer is the order you want in the final document, begin by opening the first PDF in Acrobat 5. Next, in the File Explorer, select the remaining PDFs to merge. Finally, click the first PDF in this selection, as shown in Figure 5-1, drag the selection over the PDF currently open in Acrobat, and then drop it. A dialog will open, asking where you want to insert these PDFs. Select After Last Page and they will be appended to the first PDF. Review the document to ensure the PDFs were appended in the correct order.
pdftk is a command-line tool for doing everyday things with PDF documents. It can combine PDF documents into a single document or split individual pages out into a new PDF document. Read [Hack #79] to install pdftk and our handy command-line shortcut. pdftk is free software.
Open a command prompt and then change the working directory to the folder that holds the input PDF files. Or, you can open a handy command line by right-clicking the folder that holds your input PDF files and selecting Command from the context menu.
To combine pages into one document, invoke pdftk like so:
pdftk <input PDF files> cat [ <input PDF pages> ] output <output PDF filename>
A couple of quick examples give you the flavor of it. Here is an example of combining the first page of in2.pdf, the even pages in in1.pdf, and then the odd pages of in1.pdf to create a new PDF named out.pdf:
pdftk A=in1.pdf B=in2.pdf cat B1 A1-endeven A1-endodd output out.pdf
Here is an example of combining a folder of documents to create a new PDF named combined.pdf. The documents will be ordered alphabetically:
pdftk *.pdf cat output combined.pdf
Now, let's dig into the parameters:
Input PDF filenames are associated with handles like so:
<input PDF handle> = <input PDF filename>
where a handle is a single, uppercase letter. For example, A=in1.pdf associates the handle A with the file in1.pdf.
A=in1.pdf B=in2.pdf C=in3.pdf
A file handle is necessary only when combining specific pages or when the input file requires a password.
Describe input PDF page ranges like so:
<input PDF handle> [ <begin page number> [- <end page number> [ <qualifier> ]]]
where the handle identifies one of the input PDF files, and the beginning and ending page numbers are one-based references to pages in that PDF file. The qualifier can be even or odd. A few examples make this clearer. If A=in1.pdf:
Means the first 12 pages of in1.pdf
Means pages 2, 4, 6, 8, 10, and 12
Means pages 12, 10, 8, 6, 4, and 2
Means all the pages from in1.pdf
Means the same thing as A1-end
Means page 10 from in1.pdf
You can see from these examples that page ranges also specify the output page order. Notice the keyword end, which refers to the final page in a PDF.
Specify a sequence of page ranges like so:
A1 B1-end C5
When combining all the input PDF documents in their given order, you can omit the <input PDF pages> section.
The output PDF filename must be different from any of the input filenames.
If any of the input files are encrypted, you will need to supply their owner passwords [Hack #52] .