csvcat.py

# Concatenate a set of CSV files passed as arguments. The headers of all
# the files must match. Output will be a single header row, followed
# by all the rows from all the CSV files.

import sys

if len(sys.argv) == 1:
	sys.exit("No arguments supplied")

buffer = []
headers = ""

for arg in sys.argv[1:]:
	file_lines = open(arg).readlines()

	if len(file_lines) == 0:
		sys.exit("Empty file: %s" % arg)
	if headers == "":
		headers = file_lines[0]
	elif headers != file_lines[0]:
		sys.exit("Headers do not match in file: %s" % arg)
	
	buffer += file_lines[1:]

print headers, ''.join(buffer)