When an ipython notebook is minorly corrupt or otherwise unopenable and you've exhausted other recovery options, you can try running this function to print out all of the code and headings in such a way that you could recreate the notebook by copy-pasting them into a fresh notebook. It's not super fun, but better than nothing in some cases.

show_nb_inputs.py

"""
usage: python show_nb_inputs.py notebook.ipynb
"""


import sys
import io
from IPython.nbformat import current


def show_notebook_inputs(nb):
    """print text needed to recreate a notebook"""
    k = 1
    for ws in nb.worksheets:
        for cell in ws.cells:
            if cell.cell_type == 'code':
                print "#------------code block {0}------------\n".format(k)
                print cell.input
                print "\n\n"
                k += 1
            elif cell.cell_type == 'heading':
                print "#------------heading type {0}------------\n".format(cell.level)
                print "# " + cell.source
                print "\n\n"
                
 
if __name__ == '__main__':
    fname = sys.argv[1]
    with io.open(fname, 'r') as f:
        nb = current.read(f, 'json')
    show_nb_inputs(nb)