Logger module in child processes from os.fork()
Thomas, your solutions looks good. I have few remarks regarding the code style.


The following code looks a bit strange to me:

for num in range(number + 1):
    # prime numbers are greater than 1
    if num &gt; 1:
        for i in range(2,num):
        ...


You can easily replace it with:

for num in range(2, number + 1):
    for i in range(2, num):
    ...

Do not use string concatenations, they are making your code less readable. Better use the .format() method of the string:

'child:' + str(os.getpid()) + ':' + str(num)

# Better:
'child:{pid}:{num}'.format(pid=os.getpid(), num=num)

In order to not put the meta information to every logging request, you can use logging formatters. Please check that doc for more details: https://docs.python.org/2/howto/logging-cookbook.html#using-logging-in-multiple-modules.
To simplify logging creation and make a code a bit more readable, you can create a function get_logger:

def get_logger(pid):
    file_name = 'logs/child_primes_{}.log'.format(pid)
    file_handler = logging.FileHandler(file_name)
    name = 'child:{}'.format(pid)
    logger = logging.getLogger(name)
    logger.addHandler(file_handler)
    # TODO: Add a formater here
    return logger