This is a series highlighting best-of-breed utilities. We cover a wide range of utilities including tools that boost your productivity, help you manage your workflow, and lots more besides. There’s a complete list of the tools in this series in the Summary section.
Optical Character Recognition (OCR) is a visual recognition process that turns printed or written text into an electronic character-based file. This makes the document searchable and offers the ability to copy-paste its contents.
PDF is generally considered to be an excellent format for storing and exchanging scanned documents. Unfortunately, PDFs aren’t trivial to modify. OCRmyPDF makes it easy to apply image processing and OCR to existing PDFs. The program add an OCR text layer to scanned PDF files. It’s a command-line only affair.
Let’s get an important distinction out of the way. If you create a PDF document from an electronic source, there will already be an OCR layer applied. Native PDF files have an internal structure that can be read and interpreted. These “generated” PDF documents already contain characters that have an electronic character designation. The most popular office suite for Linux is LibreOffice. That suite automatically applies a text layer to documents exported to the PDF format. For this scenario, you don’t need OCRmyPDF.
PDF documents are also created by scanning a paper document into an electronic format. Typically, this is with a flatbed scanner. The scanner takes a “snapshot” of the paper document. This snapshot is turned into a PDF (or another format such as JPG and TIFF). This is a “scanned” PDF document which often won’t have an OCR layer. Want to add that text layer? Step forward OCRmyPDF.
Installation procedure will depend on the Linux distro you’re using. On my Arch based system, installation is trivial, as there’s a package in the Arch User Repository.
Installing the package pulls in a number of other programs including tesseract, img2pdf, pngquant, unpaper, and various Python packages.
You’ll also need a language pack.
I’m using the English language pack for Tesseract. But Tesseract supports most languages. Just install the relevant language pack(s) for your requirements. And there’s support for multilingual documents.
Complete list of articles in this series:
|tmux||A terminal multiplexer that offers a massive boost to your workflow|
|lnav||Advanced log file viewer for the small-scale; great for troubleshooting|
|Paperwork||Designed to simplify the management of your paperwork|
|Abricotine||Markdown editor with inline preview functionality|
|mdless||Formatted and highlighted view of Markdown files|
|fkill||Kill processes quick and easy|
|Tusk||An unofficial Evernote client with bags of potential|
|Ulauncher||Sublime application launcher|
|McFly||Navigate through your bash shell history|
|LanguageTool||Style and grammar checker for 30+ languages|
|peco||Simple interactive filtering tool that's remarkably useful|
|Liquid Prompt||Adaptive prompt for Bash & Zsh|
|Ananicy||Shell daemon created to manage processes’ IO and CPU priorities|
|cheat.sh||Community driven unified cheat sheet|
|ripgrep||Recursively search directories for a regex pattern|
|exa||A turbo-charged alternative to the venerable ls command|
|OCRmyPDF||Add OCR text layer to scanned PDFs|
|Watson||Track the time spent on projects|
|fontpreview||Quickly search and preview fonts|
|fd||Wonderful alternative to the venerable find|