Alternatively, you can combine all of your documents in Microsoft Words and export them to a PDF.

How PDFtk Works

PDFtk stands for “PDF Toolkit.” PDFtk Server allows you to merge PDF documents, split PDF pages into new documents, rotate PDF pages, decrypt and encrypt, update metadata, apply watermarks, and much more. It is free, open source software available for Windows, Linux, and macOS. Best of all, it does not require Acrobat or any other Adobe products to work. Note: there is also a PDFtk Free, applicable only for Windows. It’s a graphical interface that allows you to add multiple PDF files and merge them into one.

How to Install PDFtk on Linux

For Linux (using Ubuntu), you can install it with the command: or PDFtk is also available in most repositories, so you can easily install it from your package manager/Software Center.

Using PDFtk to Combine Multiple PDFs

That is all it takes. Be sure to check the new PDF file to be sure all of the new pages display correctly. The merging process is seamless, painless, and should work on any regular PDF files you have. To combine multiple documents in a directory without listing each one, use wildcards (*):

How to Split, Encrypt, and Decrypt PDFs Using PDFtk

As an added bonus, PDFtk can perform many other tasks. For example, to split a PDF file’s pages into multiple documents, run the following command: This will split the document into single pages that you can manipulate as you see fit. With PDFtk, you can even merge certain pages from multiple documents into one new document. To do so, enter the following command: In this case, “A” and “B” are used as “handles” for the names of your documents. You can use as many as you need.

Encrypting and decrypting your PDF file

To encrypt your new PDF file, use the following command: where “foopass” is the password you use to encrypt the file. Change to a more secure password for your own usage. On the other hand, if you have an encrypted PDF file, you can also decrypt it with PDFtk: This only touches the surface of the many functions of PDF manipulation available with pdftk. You can use pdftk –help or access the online examples to get a good overview of the command. Note: here is another way to remove passwords from PDF files in Windows.

Using PDFtk Free on Windows

While you can use the command line version of PDFtk on Windows, PDFtk Free offers an easier-to-use graphical interface. The great part is that both PDFtk Server and PDFtk Free come together in a single installation, so you get both. Feel free to use either option. The following instructions, though, apply to PDFtk Free. The free version doesn’t have quite as many features but does still merge PDFs together. The premium upgrade is just $3.99 if you want to switch. Press “Add PDF” to add the PDF files you want to merge. Files are added to the list in the order you select them, but don’t worry about the order right now. Once added, simply drag and drop the files to create the order you want. You can also double-click the “Pages to Copy” field to select any pages you want to copy in your merged PDF. Use the “Copy Selection” and “Remove Selection” buttons to copy a selection to add it twice or remove a selection. When you’re ready, press “Create PDF” at the bottom of the window. You can also choose to open the newly created PDF or show the location of the PDF in the “Afterwards” drop-down menu. Tip: If you are looking for ways to modify the text in a PDF file, here are some ways you can do it.

Combine PDF Files With PDFTK Builder

Another option is to use PDFTK Builder. It’s another version of PDFtk that works similarly but is not created by PDFtk. Multiple versions of PDFTK Builder exist online, but one of the best is the portable app version.

Using PDF Arranger to Merge PDF Files on Linux and Windows

If you find PDFtk too complicated for you, another application you can use to merge PDF files is PDF Arranger. PDF Arranger is a fork of the old pdfshuffler and small python-gtk application that allows the user to merge or split PDF documents and rotate, crop and rearrange their pages using a simple graphical interface. You can install PDF Arranger from the Software Center or your package manager. For Windows, you can download the msi installer here.

Beyond Merging PDFs

Merging PDFs is great and all, but there’s so much more PDFtk is capable of. Naturally, PDFtk Free is limited, but one thing you can still do in both PDFtk Server and PDFtk Free is split PDFs. For Linux, you’ll need to remove pages from the output file. You can remove as many pages as you need. Use the following as an example: Other things you can do with PDFtk Free include:

Rotate (premium only) Add stamps or watermarks (premium only) Encrypt documents (premium only)

Other things you can do with PDFtk Server (both Linux and Windows) include:

Rotate pages Encrypt and decrypt pages Fill out PDF forms Add stamps and watermarks Repair corrupted files (not always possible but does recover the file if possible) Add PDF bookmarks and metadata Break a PDF into single pages Unpack attachments Attach files to PDF documents

As you can see, this seemingly simple tool can do so much more than merge PDF files. Once you get the hang of the commands, it’s a great all-in-one PDF utility. In addition to merging, you can also compress your PDF documents in both desktop and mobile.

Use LibreOffice Draw

If you already use LibreOffice as a Microsoft Office alternative, just use LibreOffice Draw to combine your files. While Writer doesn’t let you do this, Draw does. If you prefer using LibreOffice Writer over Microsoft Word, check out this keyboard shortcuts guide.

Other Tools to Combine PDF Files on Windows and Linux

While this post focuses mainly on PDFtk, it’s not your only option. It’s just easy to use and highly effective. But, if you’d rather branch out and try something else, give these tools a try:

ImageMagick – this tool is mainly for image editing and optimization, but it also features a PDF merger tool. It’s free to use and cross-platform across Linux, Windows, macOS, iOS, and Android. Ghostscript – this command line utility lets you manipulate PDF, XPS, and PostScript files. It’s designed for Linux but can be implemented in Windows too. Pdfmod – this command line utility lets you quickly combine PDF files. pdfunite – another command line utility that does exactly what it says. It unites PDF files in Linux. PDF Chain – this is actually another GUI version of PDFtk, but it’s an older tool and doesn’t always work well on newer systems. However, if you have an older version of Windows or Linux, this could be a great option. pdfshuffler – this Linux tool lets you merge, split, and crop PDF files. It’s very basic but serves its intended purpose.

Lastly, you can also combine multiple PDFs on your iPhone. Image credit: Pixabay Also, if you need commercial support for use in a business, you can purchase a one-year service agreement for $79/year. You can still use PDFtk or any other tool in this post to combine PDF files, then use another tool to encrypt them.