Combine multiple CSVs into one.

csv_concat.py

import glob

files = glob.glob("*.csv")

header_saved = False
with open('output.csv', 'w') as fout:
    for file in files:
        with open(file) as fin:
            header = next(fin)
            if not header_saved:
                fout.write(header)
                header_saved = True
            for line in fin:
                fout.write(line)