MacOS – Launchd/Launchctl – pre and post scripting

There is no way to do this, "launchd" is the master process, the equivalent of "init" in other unix systems, the only way in any other daemon would be to perform some sort of kill -HUP to reload config files etc, but this operation is not permitted on launchd. If you look it up in the process table it is the number 1 process, every other process that is currently running is in some way a child of it, so a reboot is the only way to achieve this. You may have further luck in setting those environment variables in another area that is more inclined to allow restarts.

    Dans-iMac:etc stuffe$ ps -ef | grep launchd | grep -v grep
    0     1     0   0  9:40am ??         0:09.47 /sbin/launchd
   65    18     1   0  9:40am ??         1:53.64 /usr/sbin/mDNSResponder -launchd
  213    73     1   0  9:41am ??         0:02.55 /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/A/Resources/usbmuxd -launchd
    0    85     1   0  9:41am ??         0:00.08 /System/Library/CoreServices/ODSAgent.app/Contents/MacOS/ODSAgent -launchd
   89   230     1   0  9:41am ??         0:00.01 /sbin/launchd
  501   238     1   0  9:41am ??         0:00.23 /sbin/launchd
  501   933   238   0 10:53am ??         0:00.01 /System/Library/CoreServices/AirPort Base Station Agent.app/Contents/MacOS/AirPort Base Station Agent -launchd -allowquit

EDIT:

Of course, missing the obvious solution that you can add the relevant variables into the config file, and then just run the commands manually in order to escape the need for a reboot, nothing that only newly start programs will take account of any changes. I found this page which explains it in more detail:

Environment variables set in launchd will be available to all programs on the system. However since $HOME/.launchd.conf is not supported, this approach is used for global environment variables only.

The /etc/launchd.conf file contains a list of commands to be run by launchctl during startup. However environment variables set in /etc/launchd.conf cannot have spaces and cannot reference other environment variables; launchctl when run in Terminal does not suffer these limitations. Do note that /etc/launchd.conf does not exist by default, so we will need to create it.

A reboot is necessary to load the contents of /etc/launchd.conf. However if you were to run the corresponding launchctlcommands in Terminal, you can alleviate the need for the reboot. Just remember that if you only do the launchctl commands, and do not put the entries in /etc/launchd.conf, it will not persist after reboot.

If you want to have a system wide environment variable that uses spaces or be dependent upon another environment variable, you can put the launchctl commands into one of the files Terminal reads. You will have to quit and relaunch Terminal to access the newly set variables.

Okay, I found a solution...

Chris Johnsen has a good writeup of what causes this problem on github.

His tools work, but a better solution, if you have homebrew installed to:

brew install reattach-to-user-namespace

Then in your ~/.tmux.conf add these lines:

set-option -g default-command "reattach-to-user-namespace -l zsh" # or bash
bind C-c run "tmux show-buffer | reattach-to-user-namespace pbcopy"
bind C-v run "reattach-to-user-namespace pbpaste | tmux load-buffer - && tmux paste-buffer"

The first line ensures your shell can talk to pbpaste, pbcopy and launchctl now with no worries.

The second line lets you copy the tmux paste buffer into the Mac's paste buffer by typing control-b control-c (replace control-b with your tmux prefix key).

The third line will directly paste the Mac's paste buffer by typing control-v. As a side-effect it copies the Mac's paste buffer into tmux's paste buffer.

I'd prefer if I could nuke tmux's paste buffer entirely and have it paste directly into the Mac`s paste buffer, but... oh well.