5 tools
Perl module (PDF 1.0–1.5) for reading and writing PDFs: extract/delete/duplicate pages, get page text/content trees, append/prepend pages from other PDFs, handle password-protected documents and permissions, list/add fonts, list/fill form fields, remove annotations, detect linearized PDFs, remove unused objects, and apply compression filters.
Go PDF processor (CLI + library) supporting PDF up to 2.0 (ISO 32000-2): validate, optimize, split, trim, and merge PDFs; encrypt/decrypt; resize, rotate, and crop pages; extract/manipulate images, fonts, and metadata; manage attachments and portfolios; validate, report, and remove digital signatures; add/remove stamps and watermarks; process forms, bookmarks, and annotations; and generate booklets, N-up/N-down layouts, grids, and posters.
R bindings for extracting content from PDFs: `pdf_text()` for per-page text, `pdf_info()` for metadata (author, creation date, tags), `pdf_toc()` for table of contents/section headers, `pdf_fonts()` for font info, embedded-attachment access, and `pdf_render_page()` to rasterize pages to bitmap (e.g. PNG/WEBP). Does not handle table extraction (recommends the `tabulizer`/`tabulapdf` package) or OCR of scanned text (recommends the `tesseract` package).
C++PDF rendering library and command-line suite — a fork of Xpdf that's become the de facto standard PDF engine underlying much of the open-source PDF ecosystem, powering tools like Evince, Okular, and countless downstream wrappers. Ships pdftotext, pdfimages, pdftoppm, pdftocairo, pdftohtml, pdftops, pdfinfo, pdffonts, pdfdetach, pdfattach, pdfseparate, pdfunite, and pdfsig, covering text/image extraction, page rendering, format conversion, metadata, attachments, and signature verification.
PDF viewer plus a full command-line toolset (pdftotext, pdftops, pdftoppm, pdftopng, pdftohtml, pdfinfo, pdfimages, pdffonts, pdfdetach) for viewing PDFs and converting them to text, PostScript, image, or HTML, alongside metadata, image, font, and attachment extraction. The original codebase Poppler itself forked from; poppler-utils has since become the more actively maintained fork of these same tools, but Xpdf continues independent development under its original author.