Get all files referenced by a Nuke file knob

gistfile1.py

def _collect_file_knob(node):
    # disallow locally-cached paths, otherwise evaluating gives localised path
    if node.knob('cacheLocal'):
        orig = node['cacheLocal'].value()
        node['cacheLocal'].setValue('never')

    # Frame range to evaluate
    fr = nuke.FrameRange(node['first'].value(), node['last'].value(), 1)

    # Evaluation context thing, modified later
    output_context = nuke.OutputContext()

    files = []
    for viewnumber in range(output_context.viewcount()):
        # Loop over each view

        # Skip "default" view
        viewname = output_context.viewname(viewnumber)
        if viewname not in nuke.views():
            continue

        # Set evaluation context view number
        output_context.setView(viewnumber)

        # Evaluate file for current view and frame
        for framenum in fr:
            # Loop over each frame
            output_context.setFrame(framenum)

            # ..and evaluate the file knob for this view/frame
            evaluated_filepath = node['file'].getEvaluatedValue(output_context)
            files.append(evaluated_filepath)

    # Restore original cacheLocal setting
    node['cacheLocal'].setValue(orig)
    return files


print _collect_file_knob(nuke.selectedNode())