Deprecation warning
This repository was moved to github.com/zaphB/paperman and is not maintained anymore.
Installation notes
Move shell scripts (*.sh) to the location you wish to create your library at. In the first lines of "collect-papers.sh" you can change a few settings: The "srcDir", from where papers are collected, "MAX_FILENAME_LEN" and "MAX_KEYWORD_LEN", which are the maximum lengths for filenames and biblatex bibliography keys, respectively. Start script (in background) to keep collecting papers and adding them to your library.
If you use Firefox open 'about:config' and set 'dom.allow_scripts_to_close_windows' to 'true'.
Install Tampermonkey. Go to tampermonkey settings, section "Downloads BETA". Select the download mode "Browser API" (at least for chromium and chrome browsers, Firefox works anyhow). Add ".bib", ".ris" and ".pdf" to the "Whitelisted File Extensions". Create a new userscript, copy and paste the contents of "paper-man.user.js" and save.
Done!