prints all term256 colors out. if you chmod +x it, it will run as an executable file.

colortest.py

#!/usr/bin/python
from __future__ import print_function
import argparse, sys

parser = argparse.ArgumentParser()
parser.add_argument("-f", "--flat", help="Print without blocking", dest="flat",
	action="store_true")
args = parser.parse_args()

mainbase = "\033[38;5;{}m"
backgroundbase = "\033[48;5;{}m"
reset = "\033[0m"

toprint = [["" for i in range(16)] for i in range(16)]

if __name__ == "__main__":
	for i in xrange(0, 256, 16):
		for j in xrange(16):
			num = i+j
			strnum = str(num)
			if num < 100:
				strnum = "0" + strnum
				if num < 10:
					strnum = "0" + strnum
			toprint[i/16][j] = strnum+" "+mainbase.format(num)+backgroundbase.format(num)+"===="+reset
	sep = "\n" if args.flat else " "
	if not args.flat:
		toprint = map(None, *toprint)
	sys.stdout.write("\n".join([sep.join(i) for i in toprint])+"\n")