A script to process azw3, epub, and mobi into text files using calibre ebook-convert

convert.py

directories = ['azw3', 'epub', 'mobi']
conversion_space = "convert"
sink = open('/dev/null', 'w')

def convert_book(input, output):
    subprocess.call("ebook-convert" + " " + input  + " " + output, shell=True, stdout=sink, stderr=sink)

for directory in directories:
    conversion_directory = os.path.join(directory, conversion_space) 
    if not os.path.exists(conversion_directory):
        os.makedirs(conversion_directory)
        print("Creating {} directory".format(directory))
    # Convert all files ending in the directory name
    files_to_convert = [file for file in os.listdir(directory) if directory in file]
    for file in files_to_convert:
        # Remove extension for conversion to TXT 
        base = file.split("." + directory)[0]
        output = base + ".txt"
        full_input = shlex.quote(os.path.join(directory, file))
        full_output = shlex.quote(os.path.join(directory, os.path.join(conversion_space, output)))
        print("Creating {}".format(output))
        convert_book(full_input, full_output)

sink.close()