find /mnt/docs -name '*.pdf' | parallel pdfgrep -Ri 'искомая подстрока'
... | parallel -j15 pdfgrep -HRiF --color=always 'искомая подстрока'
parallel -j15 grep -HRiF --color=always 'искомая строка' ::: /mnt/docs
#ripgrepall is a #grep for everything.
#rga performs regex searches on many different container filetypes, including #PDF, #zip, #tar, #SQLite, and #docx. rga uses #ripgrep for searching, which makes searches extremely fast, allowing it to outperform #pdfgrep in speed (some matches are missed, however). rga performs caching for faster repeat searches.
Website 🔗️: https://github.com/phiresky/ripgrep-all
#ripgrep is even faster when searching in #PDF files than #pdfgrep + #parallel
https://karl-voit.at/2021/01/11/pdfgrepp/
#publicvoit
#pdfgrep is a #PDF file searcher.
pdfgrep is a search program that looks for #regex patterns in the text portions of a PDF file. pdfgrep is largely compatible with GNU #grep, supporting recursing directories, case insenstive regex, colorized output, etc. pdfgrep can also search in password protected PDF files.
Website 🔗️: https://pdfgrep.org/
apt 📦️: pdfgrep