Hey there! Today, I want to share a nifty little trick that I recently discovered and help me a lot – how to merge a bunch of images into a single PDF file using the Linux command line. So, let's dive right into it!
The magic tool that we're going to use here is
convert, which is a part of the
ImageMagick package – a powerful suite of command-line tools for image manipulation. If you don't have it installed, you can usually install it using your package manager. For instance, on Debian-based systems, you'd run:
sudo apt-get install imagemagick
ImageMagick's security policies are designed to ensure that image and file operations are performed in a safe and secure manner, preventing potential abuses. This means that certain features, such as writing PDF files, might be disabled by default for security reasons.
It PDF writing is disable you may encounter this error:
attempt to perform an operation not allowed by the security policy 'PDF' @ error/constitute.c/IsCoderAuthorized/421
To enable writing PDF files using the
convert command, you'll need to modify ImageMagick's security policies. Here's how to do it:
Locate the policy file: ImageMagick's policy files are usually located in the
/etc/ImageMagick-<version>/directory. The file name is
Edit the policy file: Open the
policy.xmlfile with a text editor as an administrator (use sudo for administrative rights).
<policymap>section: Inside the policy.xml file, you'll find a
<policymap>section. This is where you'll define policies for each file format.
Enable PDF writing: To enable writing PDF files, locate the line that corresponds to the PDF pattern. Modify the value of rights to allow PDF writing. For example:
<policy domain="coder" rights="read | write" pattern="PDF" />
The basic syntax of the
convert command for merging images into a PDF is as follows:
convert image1.jpg image2.png output.pdf
You simply list the input images in the order you want them to appear in the PDF, followed by the desired output PDF file name.
But what if you have a bunch of images in a folder that you want to merge in a specific order? No worries, we can use shell globbing to our advantage. Here's how:
convert *.jpg output.pdf
This command would merge all the JPEG images in the current folder into a single PDF named
If you're seeking solutions to a problem or need expert advice, I'm here to help! Don't hesitate to book a call with me for a consulting session. Let's discuss your situation and find the best solution together.