#+author: Nicola Ferru
#+email: ask.nfvblog@outlook.it
#+title: PDF COMPressor
#+description: A simple bash script to compress PDF files using Ghostscript with interactive preview and multiple DPI presets.

This script is meant to simplify ghostscript syntax and also to have a convenient and practical solution for *PDF compression*.

* Dependence                                         :dependence:ghostscript:
The only dependencies you need to install =ghostscript=. To do this, just go to the repo of your Linux distro or to brew if it is mac os x and install the package of the same name. For the rest the script can be put in a path to be more convenient.
** Arch Linux                                                         :Arch:
#+begin_src shell
  sudo pacman -S ghostscript
#+end_src
** Debian Linux and derived                                  :debian:ubuntu:
#+begin_src shell
  sudo apt install ghostscript
#+end_src
** Fedora Linux and derived                                  :centos:fedora:RedHat:
#+begin_src shell
  sudo dnf install ghostscript
#+end_src
** Mac Os X                                                         :macosx:
#+begin_src shell
  brew install ghostscript
#+end_src
Of course it is also possible to install it manually.

* Installation                                                      :install:
To make the script globally accessible, you can move it to your local bin directory:
#+begin_src shell
  chmod +x pdfcompressor.sh
  sudo mv pdfcompressor.sh /usr/local/bin/pdfcompressor
#+end_src

* Usage :usage:examples:
Once installed, you can use the script with the following syntax:
#+begin_src shell
  pdfcompressor [option] input.pdf [output.pdf]
#+end_src

** Options
| Flag | Long Name     | Description                                           |
|------+---------------+-------------------------------------------------------|
| -h   | --help        | Show the help message and exit.                       |
| -f   | --format      | Select a specific compression level.                  |
| -fl  | --format-list | Display all available compression DPI levels.         |
| -p   | --prev        | Interactive mode with live size comparison (Preview). |

** Practical Examples

*** Basic Compression
If you don't specify an output name, the script creates =filename_comp.pdf= with default settings:
#+begin_src shell
  pdfcompressor document.pdf
#+end_src

*** Specific Quality Level
Compress a file specifically for screen viewing (low res, small size):
#+begin_src shell
  pdfcompressor -f screen input.pdf output_small.pdf
#+end_src

*** Interactive Preview (Recommended)
This is the most useful feature. It allows you to test different levels and see the final file size before saving:
#+begin_src shell
  pdfcompressor -p my_heavy_file.pdf
#+end_src

** Compression Levels (Ghostscript standard)
- *screen*: 72 dpi (smallest size, lowest quality).
- *ebook*: 150 dpi (perfect for digital reading).
- *preprint*: 300 dpi (high quality, color preserving).
- *printer*: 300 dpi (optimized for physical printing).
- *default*: GS standard balance.