# Mac os environment variables

Suppose you install some program into your home directory (i had installed mercurial from source). To use it you have to patch PATH variable.

To achieve this, you needed to modify, for example, local .profile file (its undesirable to modify global config like etc/profile). So your .profile file contains something like this:

export PATH=$ADDITIONAL_PATH:$PATH


It wokrs great from terminal. But you cant use variable defined such way from programs launched throught spotlight, because all apps started from gui interface of Mac Os has its own list of environemnt variables (independent from terminal). In my case i cant access mercurial from emacs launched from spotlight.

You can access environment variables used by gui apps in such way:

$launchctl getenv PATH  To change it: $ launchctl setenv PATH $SOME_PATH  Its reasonable to preserve original PATH while patching. So you want to add your$ADDITIONAL_PATH into gui PATH

# save old path
OLD_GUI_PATH=launchctl getenv PATH
# construct new path
NEW_GUI_PATH=$ADDITIONAL_PATH:$OLD_GUI_PATH
# update gui path
launchctl setenv PATH $NEW_GUI_PATH  These changes are not persisted, so you will miss it after restart. Hhhhaaa, add this into .profile. But .profile is evaluated at every launch of terminal. So you have conditionally patch your environent variables, in other words .profile must be idempotent. Multiple evaluation of .profile must have same effect as single evaluation, othewise after terminal app launches several times, your PATH looks like this: ADDITIONAL_PATH:ADDITIONAL_PATH:ADDITIONAL_PATH...:$PATH


So final version of the script:

# patch PATH for terminal programs
# check variable hasnt already patched
if [[ $PATH != *$ADDITIONAL_PATH* ]]
then
export PATH=$ADDITIONAL_PATH:$PATH
fi

# patch PATH for gui (and spotlight in particular)
# preserve old values
OLD_GUI_PATH=launchctl getenv PATH
# check if has not already patched
if [[ $OLD_GUI_PATH != *$ADDITIONAL_PATH* ]]
then
NEW_GUI_PATH=$ADDITIONAL_PATH:$OLD_GUI_PATH
launchctl setenv PATH \$NEW_GUI_PATH
fi


Looks like a little bit cumbersome, but works ! If there is easier way, i would be glad to know.

Update: There is problem with this solution. launchctl settings are updated during first load of .profile file. So if you has not opened terminal app yes (for example after restart), you cant use this customization.
Updated solution can be found here.