Enable/Disable a number of cores on a Linux system

cores.py

#!/usr/bin/env python3
import sys

MAX_CORES = 12

if len(sys.argv) >= 2:
    n = int(sys.argv[1])

    if n > MAX_CORES or n < 1:
        sys.exit(1)

    for i in range(1, n):
        path = "/sys/devices/system/cpu/cpu{}/online".format(i)
        with open(path, "w") as f:
            f.write("1")
    for i in range(n, MAX_CORES):
        path = "/sys/devices/system/cpu/cpu{}/online".format(i)
        with open(path, "w") as f:
            f.write("0")
else:
    enabled = 1
    for i in range(1, MAX_CORES):
        path = "/sys/devices/system/cpu/cpu{}/online".format(i)
        with open(path, "r") as f:
            c = f.read(1)
            if c == "1":
                enabled += 1
    print(enabled)