import os

input_dir = '/var/data'
output_file = '/var/result/data.txt'

def get_first_line_from_files(input_directory, output_path):
    with open(output_path, 'w') as outfile:
        for filename in os.listdir(input_directory):
            file_path = os.path.join(input_directory, filename)
            if os.path.isfile(file_path):
                with open(file_path, 'r') as infile:
                    first_line = infile.readline().strip()
                    outfile.write(first_line + '\n')

if __name__ == "__main__":
    get_first_line_from_files(input_dir, output_file)