import nuke, os, subprocess

def get_open_files():
    found_knobs = []
    found_files = []

    for node in nuke.allNodes():
        try:
            found_knobs.append(node.knob('file').getValue())
        except:
            pass

    for i in found_knobs:
        for name in os.listdir(os.path.dirname(i)):
            filepath = os.path.join(os.path.dirname(i), name)
            if os.path.isfile(filepath) and filepath not in found_files:
                found_files.append(filepath)

    return len(found_files)

def get_ulimit():
    process = subprocess.check_output("ulimit -s", stderr=subprocess.STDOUT, shell=True)
    return int(process.strip())

if get_open_files() > get_ulimit():
    print 'Reached Ulimit'
else:
    print 'Still room in ulimit'