Este script Python [*] faz exatamente isso:
"""
Show/Modify/Append registry env-vars (ie `PATH`) and notify Windows-applications to pickup changes.
First attempts to show/modify HKEY_LOCAL_MACHINE (all users), and
if not accessible due to admin-rights missing, fails-back
to HKEY_CURRENT_USER.
Write and Delete operations do not proceed to user-tree if all-users succeed.
Syntax:
{prog} : Print all env-vars.
{prog} VARNAME : Print value for VARNAME.
{prog} VARNAME VALUE : Set VALUE for VARNAME.
{prog} +VARNAME VALUE : Append VALUE in VARNAME delimeted with ';' (i.e. used for `PATH`).
{prog} -VARNAME : Delete env-var value.
Note that the current command-window will not be affected,
changes would apply only for new command-windows.
"""
import winreg
import os, sys, win32gui, win32con
def reg_key(tree, path, varname):
return '%s\%s:%s' % (tree, path, varname)
def reg_entry(tree, path, varname, value):
return '%s=%s' % (reg_key(tree, path, varname), value)
def query_value(key, varname):
value, type_id = winreg.QueryValueEx(key, varname)
return value
def yield_all_entries(tree, path, key):
i = 0
while True:
try:
n,v,t = winreg.EnumValue(key, i)
yield reg_entry(tree, path, n, v)
i += 1
except OSError:
break ## Expected, this is how iteration ends.
def notify_windows(action, tree, path, varname, value):
win32gui.SendMessage(win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 'Environment')
print("---%s %s" % (action, reg_entry(tree, path, varname, value)), file=sys.stderr)
def manage_registry_env_vars(varname=None, value=None):
reg_keys = [
('HKEY_LOCAL_MACHINE', r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment'),
('HKEY_CURRENT_USER', r'Environment'),
]
for (tree_name, path) in reg_keys:
tree = eval('winreg.%s'%tree_name)
try:
with winreg.ConnectRegistry(None, tree) as reg:
with winreg.OpenKey(reg, path, 0, winreg.KEY_ALL_ACCESS) as key:
if not varname:
for regent in yield_all_entries(tree_name, path, key):
print(regent)
else:
if not value:
if varname.startswith('-'):
varname = varname[1:]
value = query_value(key, varname)
winreg.DeleteValue(key, varname)
notify_windows("Deleted", tree_name, path, varname, value)
break ## Don't propagate into user-tree.
else:
value = query_value(key, varname)
print(reg_entry(tree_name, path, varname, value))
else:
if varname.startswith('+'):
varname = varname[1:]
value = query_value(key, varname) + ';' + value
winreg.SetValueEx(key, varname, 0, winreg.REG_EXPAND_SZ, value)
notify_windows("Updated", tree_name, path, varname, value)
break ## Don't propagate into user-tree.
except PermissionError as ex:
print("!!!Cannot access %s due to: %s" %
(reg_key(tree_name, path, varname), ex), file=sys.stderr)
except FileNotFoundError as ex:
print("!!!Cannot find %s due to: %s" %
(reg_key(tree_name, path, varname), ex), file=sys.stderr)
if __name__=='__main__':
args = sys.argv
argc = len(args)
if argc > 3:
print(__doc__.format(prog=args[0]), file=sys.stderr)
sys.exit()
manage_registry_env_vars(*args[1:])
Abaixo estão alguns exemplos de uso, supondo que ele tenha sido salvo em um arquivo chamado setenv.pyem algum lugar do seu caminho atual. Observe que nesses exemplos eu não tinha direitos de administrador , portanto as alterações afetaram apenas a árvore de registro do meu usuário local:
> REM ## Print all env-vars
> setenv.py
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
HKEY_CURRENT_USER\Environment:PATH=...
...
> REM ## Query env-var:
> setenv.py PATH C:\foo
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
!!!Cannot find HKEY_CURRENT_USER\Environment:PATH due to: [WinError 2] The system cannot find the file specified
> REM ## Set env-var:
> setenv.py PATH C:\foo
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
---Set HKEY_CURRENT_USER\Environment:PATH=C:\foo
> REM ## Append env-var:
> setenv.py +PATH D:\Bar
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
---Set HKEY_CURRENT_USER\Environment:PATH=C:\foo;D:\Bar
> REM ## Delete env-var:
> setenv.py -PATH
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
---Deleted HKEY_CURRENT_USER\Environment:PATH
[*] Adaptado de: http://code.activestate.com/recipes/416087-persistent-environment-variables-on-windows/