EnvPane - An OS X preference pane for environment variables
EnvPane is a preference pane for Mac OS X 10.8 (Mountain Lion) that lets you set environment variables for all programs in both graphical and terminal sessions. Not only does it restore support for
~/.MacOSX/environment.plist in Mountain Lion, it also publishes your changes to the environment immediately, without the need to log out and back in. This works even for changes made by manually editing
~/.MacOSX/environment.plist, not just changes made via the preference pane.
Mac OS X releases prior to Mountain Lion (10.8) included support for
~/.MacOSX/environment.plist, a file that contained session-global, per-user environment variables. Starting with Mountain Lion, support of this well documented and popular mechanism was dropped without an official announcement or explanation by Apple. It may have been in response to the Flashback trojan which used that file to inject itself into every process, but this is a wild guess, especially considering that there is a relatively easy workaround, as demonstrated by the existence of this utility.
EnvPane includes (and automatically installs) a
launchd agent that runs 1) early after login and 2) whenever the
~/.MacOSX/environment.plist changes. The agent reads
~/.MacOSX/environment.plist and exports the environment variables from that file to the current user's
launchd instance via the same API that is used by
launchctl setenv and
TODO: Mention RCEnvironment
TODO: Mention /etc/launchd.conf and ~/.launchd.conf
Mac OS X 10.8, Mountain Lion or higher.
- Download the binary package
- Choose Install for this user only
Do not use the Install for all users option. See the FAQ.
When you open the Environment Variables preference pane, you will see a simple two-column table that lists the environment variables from your
~/.MacOSX/environment.plist. If that file doesn't exist, the table will be empty but the file will be created as soon as you you add an entry to the table. To add an environment variable by clicking the
+ button. Specifying the name the new variable, hit
TAB and specify the value. Hit Enter. To modify a variable, double-click its name or value. Make the desired changes and hit
Enter. To delete an environment variable,
Changes are effective immediately in all subsequently launched applications. There is no need to reboot or log out and back in. Running applications will not be affected . You need to quit and relaunch the application, in order for your changes to take effect.
- Open System Preferences
- Right click Environment Variables
- Select Remove Environment Variables Preference Pane
The uninstallation should be clean. I went to great lengths in ensuring that removing the preference pane doesn't leave orphaned files on the system. The
~/.MacOSX/environment.plist will not be removed.
Fix: Preference pane fails to load if ~/Library/LaunchAgents is missing (issue #2)
Fix: Preference pane fails to load if ~/.MacOSX or ~/.MacOSX/environment.plist are missing (issue #1).
- Mac OS X 10.8, Mountain Lion
- Xcode 4.5.x (I use 4.5.2)
- A copy of Apple's
launchdsource tree, available on Apple Open Source under the Apache License 2.0. The current version of EnvPane was compiled against launchd-442.26.2
- David Parsons' Discount C library by for processing John Gruber's Markdown. Install the library as described on the project page. Using the default installation prefix of
/usr/localis recommended. The current version of EnvPane was compiled against version 2.1.5a of the library.
- Clone the EnvPane repository on Github
- Open the Xcode project
- At the project level, adjust the
launchd_source_dircustom build setting to point to the copy of the launchd source tree
- Build the project
Why can't I install the preference pane for all users?
There are two reasons. The first one is a technicality: the environment variables configured via the preference pane are actually set by a launchd agent contained in the bundle. The agent uses launchd's
WatchPath mechanism in order to be notified when the user's
~/.MacOSX/environment.plist changes. Unfortunately, there is no way to specify a
WatchPath that is relative to the user's home directory. By installing the EnvPane preference pane for individual users, each instance can use a separate copy of the agent configuration in
~/Library/LaunchAgents as opposed to globally in
The second reason is that cleanly uninstalling the agent would be more complex for a preference pane that was installed globally for all users. Apple is eagerly deprecating privilege escalation mechanism left and right, leaving the half-baked
SMJobBless and the rudimentary
authopen. I'm not saying it couldn't be done, I'm just not convinced it'd be worth the effort.
Why aren't running applications affected?
Say, you have a shell session running in the Terminal application. You might wonder why changes to the environment made with EnvPane don't show up in the shell's environment. The answer to this question lies in Unix' process model. When a process is forked, it inherits a copy of the environment from its parent process. The copy is independent, so changes in the parent aren't visible in the child and vice versa. Doing anything else would undoubtedly fling open Pandora's box of concurrency.
Applications launched via Finder are in fact forked by the per-user instance of
launchd, and thus inherit their environment from it. EnvPane uses
launchd's API to modify the environment of the user's
launchd instance which will then pass a copy of its modified environment to subsequently launched applications. The environment of running applications has already been copied and will not be affected.
For applications other than Terminal the only workaround is to restart the application. In Terminal, you can update the shell's environment by running
eval `launchctl export`
This will update the shell's environment, not Terminal's. Terminal's environment is still unchanged and will be passed on to each new shell window or tab. This means you will have to run the above command in each subsequently opened Terminal tab or window. Ultimately it might be better to just restart Terminal.
Copyright 2012 Hannes Schmidt Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Green Leaf icon by Bruno Maia
Copyright 2008 IconTexto http://www.icontexto.com Released under CC License Attribution-Noncommercial 3.0 http://creativecommons.org/licenses/by-nc/3.0/
Launchd by Apple Computer, Inc.
Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
Discount by David Loren Parsons
This product includes software developed by David Loren Parsons <http://www.pell.portland.or.us/~orc>