code: def expand_path(s):
      """Expand $VARS and ~names in a string, like a shell
  
      :Examples:
  
         In [2]: os.environ['FOO']='test'
  
         In [3]: expand_path('variable FOO is $FOO')
         Out[3]: 'variable FOO is test'
      """
      # This is a pretty subtle hack. When expand user is given a UNC path
      # on Windows (\\server\share$\%username%), os.path.expandvars, removes
      # the $ to get (\\server\share\%username%). I think it considered $
      # alone an empty var. But, we need the $ to remains there (it indicates
      # a hidden share).
      if os.name == "nt":
          s = s.replace("$\\", "IPYTHON_TEMP")
      s = os.path.expandvars(os.path.expanduser(s))
      if os.name == "nt":
          s = s.replace("IPYTHON_TEMP", "$\\")
      return s
  
imports: import os
  import sys
  import errno
  import shutil
  import random
  import glob
  from warnings import warn
  from hashlib import md5
  from IPython.utils.process import system
  from IPython.utils import py3compat
  from IPython.utils.decorators import undoc
label_desc: Use image node_id 15 for calling a global function with example usage: expand_path(s) and returns: s