document-comparer

Document Comparer is a program written in POSIX, which intends to keep the user up-to-date with document changes over time from the internet.

It downloads the documents from the internet, compares them to the documents in the local storage & notifies + shows the user if there are any changes between them.

I haven't found any application of this type, so I wrote it for myself.

Document format support

• PDF
• DOCX
• ODT
• EPUB

Usage

document-comparer /path/to/configuration.yml
document-comparer /path/to/configuration1.yml /path/to/configuration2.yml

• Documents are downloaded in the same directory where configuration is.
• Downloaded files in .txt format MUST remain aside from the original documents for future comparisons to work.

Configuration example

Program accepts required options title: & document-links: in .yml & .yaml configuration:

• title: serves as a general description of the document types which are being compared, so it's easier to differentiate in case of more configurations
• document-links: serves as an URL list of documents which are going to be compared

/path/to/configuration.yml:

title: Work stuff
document-links:
  - link1.com/file.pdf
  - link2.com/file2.odt

Automatic notification on selected time period

Due to inclusion of notify-send / terminal-notifier usage in the program, depending on the init & timer system, it's easy to integrate the program so Document Comparer can notify you about the changes automatically.

Program compatibility

This program should work on any Linux & BSD-based OS-es, including MacOS, if the following dependencies below are installed.

Program dependencies

Required dependencies

• id: checks if the program is ran as root.
• diff: compares the difference between old & new version of the document.
• pdftotext: Converts PDF documents to TXT.
• pandoc: Converts DOCX, ODT & EPUB documents to TXT.
• curl: checks the internet connection & downloads documents.
• sed: gets values from YML/YAML file, converts Cyrillic/whitespace coded URL filename to normal one & is used for checking if flatpak Meld is installed on Linux.
  It is tested that sed's syntax in the program works with GNU, Busybox & BSD's sed.
• xargs: passes the printf argument for the URL operation above, as POSIX shell doesn't support the argument syntax.
• mv: overwrites the old document TXT with the new one.

Recommended dependencies (for better UX)

• notify-send (Linux & BSD) / terminal-notifier (MacOS): for getting notifications of document changes & errors.
  • Fallback: printf in terminal.
• meld: for a nice GUI application showcasing the difference between old & new version of the document.
  • Linux: flatpak is preferred if available, if not, then regular program meld in PATH.
  • BSD: regular program meld in PATH.
  • MacOS: Meld DMG package to be installed either in system's or user's Applications directory.
  • Fallback: messy diff output if none of the conditions are satisfied.
• open (MacOS): Used for opening GUI applications (in this case Meld).

Most of these dependencies are installed by default in all those OS-es except meld, pdftotext & pandoc. Additionally, for MacOS, terminal-notifier is likely not installed by default.

Caveats / What doesn't work

• URLs which don't have the filename in the URL are not accepted
• YML/YAML array syntax must be in - arrayvalue, not in brackets [ arrayvalue ]