Try to figure out how much memory is free on a Unix system. Returns free memory in mB.

get_free_memory

def get_free_memory():
    """
    Try to figure out how much memory is free on a Unix system.
    Returns free memory in mB.
    """ 
    data = open("/proc/meminfo", 'rt').readlines()
    free = 0
    for line in data:
        if line.startswith("MemFree") or line.startswith("Buffers") or line.startswith("Cached"):
            items = line.split()
            free += int(items[1])
    #print "free memory is",free/1000,"mB" 
    return free/1000