System.getenv 仍会在 MacOS Mojave 上获取已删除的 env 变量值 - Java

Question

I added some exportable environment variables in my bash_profile and my profile files in the following format export "X=y". This worked as it should, now I want to remove them permanently . I've tried the following methods:

1. Deleting the exported variables from the bash_profile and the profile files, and saving the files, and calling source ~/.bash_profile and source ~/.profile.
2. Called "unset X" in terminal window. Before I could call "echo $X" which would display y, now it displays nothing.
3. Rebooting the Mac Computer.

Still however, whenever I call Java's System.getenv(X), env variable X's value (y) is still returned. What else do I need to do to completely eliminate an env variable from my system in MacOS Mojave?

Answer 1

It appears you believe environment variables are global. That is, modifying the value in one program, such as a running terminal, will affect the value in a different program. That is not how env vars work in a UNIX like OS. Each process is provided a copy of the env vars provided by the parent process. That is, they are inherited from the parent process.

The fact that you have to unset X in a terminal to remove it means that either it is being inherited by the shell from the terminal process or your shell is setting it. In the latter case the specific files read when a shell starts depends on the shell. But /etc/profile is read by most interactive shells so you might want to look there.

You say your Java app is run by Tomcat but failed to mention how Tomcat is started. That is important for the reasons I mention above.

Note that macOS uses a daemon named launchd to manage running most services. Those services are configured via "plist" files. See man launchd.plist . Those launchd config files support defining custom env vars. That is slightly unusual but worth looking at. See if any of the files in ~/Library/LaunchAgents , /Library/LaunchAgents , or /Library/LaunchDaemons mention the env var.