'''
Adds line numbers to all the lines in a .txt files.

Written By Sunjay Varma
'''

def lineNumbers(fname, widthIndex=3):
  # open the file.
  f = open(fname, 'r')

  # The list where the newly formatted lines will go.
  nlines = []

  # The number to add to the line.
  num = 1

  # go through the lines in the .txt file
  for line in f.readlines():
    # add a formatted line to nlines
    nlines.append(("%"+("."+str(widthIndex)+"i"))%num + ". " + line)
    # incrment num
    num += 1

  # close the file
  f.close()

  # write the new lines to the .txt file
  f = open(fname, 'w')
  f.write(''.join(nlines))
  f.close()

if __name__ == "__main__":
  filename = raw_input("What is the file path of your .txt file? ")
  width = raw_input("What is the maximum number of 0s before the line number? ")

  lineNumbers(filename, width)