python remove empty lines from file
import os
def remove_empty_lines(filename):
    if not os.path.isfile(filename):
        print("{} does not exist ".format(filename))
        return
    with open(filename) as filehandle:
        lines = filehandle.readlines()
    with open(filename, 'w') as filehandle:
        lines = filter(lambda x: x.strip(), lines)
        filehandle.writelines(lines)
