Decode barcodes visible on a portion of your screen.

#!/bin/bash

# Save this as a text file and make it executable.

# This script finds and decodes barcodes in a selection of the screen.
# Nice to have as a shortcut in your gnome-panel.

# When you run this script your pointer will change into a selection cursor
#  and you then must select a portion of the screen to be analyzed.

# Results will be shown in a dialog window.

# Pass a number as the first argument to wait that number of seconds before
#  invoking the screen capture command.


# This part checks for missing tools.

missing=""

which zbarimg >/dev/null || missing=${missing}" zbar-tools"
which import >/dev/null || missing=${missing}" imagemagick"
which zenity >/dev/null || missing=${missing}" zenity"

if [[ -n "${missing}" ]];
then
    echo "You seem to have some missing software that you'll need to install."
    echo "If you're on a Debian system (or Ubuntu, Linux Mint or other derivatives), you probably can install all necessary software with the following command:"
    echo "sudo apt-get install" $missing
    echo
    echo "Exiting..."
    exit
fi

# This part waits the number of seconds passed in the first argument.

if [ 0 -lt "$1" ] 2>/dev/null;
then
    sleep $1
fi

# Capture a portion of the screen with ImageMagick's import and pass
#  the resulting image to zbarimg for it to decode.

output="$(zbarimg <(import -))"

# Show the output in a window
# Also print to terminal, why not.

if [ -n "$output" ];
then
    zenity --info --text="$output"
    printf "%s\n" "$output"
else
    zenity --info --text="Nothing found."
    echo "$0: Nothing found."
fi