class_docstr: Magics to interact with the underlying OS (shell-type functionality).
      
class_docstr_tok: ["Magics","to","interact","with","the","underlying","OS","(","shell-type","functionality",")","."]
docstr: Get, set, or list environment variables.
  
  Usage:\
  
    %env: lists all environment variables/values
    %env var: get value for var
    %env var val: set value for var
    %env var=val: set value for var
    %env var=$val: set value for var, using python expansion if possible
docstr_tok: ["Get",",","set",",","or","list","environment","variables",".","Usage",":","\\","%","env",":","lists","all","environment","variables\/values","%","env","var",":","get","value","for","var","%","env","var","val",":","set","value","for","var","%","env","var=val",":","set","value","for","var","%","env","var=","$","val",":","set","value","for","var",",","using","python","expansion","if","possible"]
code: def env(self, parameter_s=""):
      """Get, set, or list environment variables.
  
          Usage:\\
  
            %env: lists all environment variables/values
            %env var: get value for var
            %env var val: set value for var
            %env var=val: set value for var
            %env var=$val: set value for var, using python expansion if possible
          """
      if parameter_s.strip():
          split = "=" if "=" in parameter_s else " "
          bits = parameter_s.split(split)
          if len(bits) == 1:
              key = parameter_s.strip()
              if key in os.environ:
                  return os.environ[key]
              else:
                  err = "Environment does not have key: {0}".format(key)
                  raise UsageError(err)
          if len(bits) > 1:
              return self.set_env(parameter_s)
      return dict(os.environ)
  
imports: from __future__ import print_function
  import io
  import os
  import re
  import sys
  from pprint import pformat
  from IPython.core import magic_arguments
  from IPython.core import oinspect
  from IPython.core import page
  from IPython.core.alias import AliasError, Alias
  from IPython.core.error import UsageError
  from IPython.core.magic import Magics, compress_dhist, magics_class, line_magic, cell_magic, line_cell_magic
  from IPython.testing.skipdoctest import skip_doctest
  from IPython.utils.openpy import source_to_unicode
  from IPython.utils.process import abbrev_cwd
  from IPython.utils import py3compat
  from IPython.utils.py3compat import unicode_type
  from IPython.utils.terminal import set_term_title
label_desc: Use image node_id 6 for calling the OSMagics obj's underlying member method code with example usage: obj.env(parameter_s) and returns: dict, self, os