old_contents: #!/usr/bin/python
  
  from __future__ import print_function
  
  import sys
  import re
  
  def main():
      m = re.compile('^(\ *[^\ \t]+)([\ \t])([^\ \t]+)(.*)')
      try:
          line = sys.stdin.readline()
          while line:
              print(re.sub(m, '\\3\\2\\1\\4', line), end='')
              sys.stdout.flush()
              line = sys.stdin.readline()
      except KeyboardInterrupt:
          pass
  
  if __name__ == '__main__':
      main()
  
new_contents: #!/usr/bin/python
  
  from __future__ import print_function
  
  import sys
  import re
  
  def main():
      m = re.compile('^(\ *[^\ \t]+)([\ \t])([^\ \t]+)[\ \t](.*)')
      try:
          line = sys.stdin.readline()
          while line:
              print(re.sub(m, '\\3\\2\\1 \\4', line), end='')
              sys.stdout.flush()
              line = sys.stdin.readline()
      except KeyboardInterrupt:
          pass
  
  if __name__ == '__main__':
      main()
  
subject: fix chanshift to replace a trailing tab with a space