Recursively convert all recently changed *.xoj files in a directory to pdf (requires a patched version of xournal)

convert_xoj.sh

#!/bin/bash
# This script converts all xournal xoj files in subdirectories of the current working directories to pdf files
# It also checks if the file was recently changed.
# To do this, it compares modification timestamps of these files with the modification timestamp of the script files itself.
# The script will also update its own modification timestamp afterwards.

SCRIPT="$(realpath "$0")"

# Converts a single xoj file to pdf. 
function convertXoj {
    XOJ="$(realpath "$1")"
    PDF="$(echo "$XOJ" | sed 's/xoj$/pdf/g')"
    # The -A option for xournal does only exist in xournal installations with a certain patch.
    # Check my github repository (https://github.com/mayjs/xournal_patched) for a version with this patch applied.
    xournal -A "$PDF" "$XOJ"
}
export -f convertXoj

# Convert every xoj file that has been changed after this file.
find . -type f -name "*.xoj" -newer "$SCRIPT" -exec bash -c 'convertXoj {}' \;
# Update the modification time of this file using touch.
touch $SCRIPT