如何在 .NET Core 中设置全局环境变量（用户范围或系统范围）

Question

In full .NET we can pass EnvironmentVariableTarget enum to Environment.SetEnvironmentVariable call:

public enum EnvironmentVariableTarget
{
    Process,
    User,
    Machine
}

With User or Machine options we can set a user-wide or system-wide variable which stays live after application end:

Environment.SetEnvironmentVariable("foo", "bar", EnvironmentVariableTarget.User);

...

> echo %foo%
bar

However, Environment.SetEnvironmentVariable doesn't accept the variable target in .NET Core. Even XML comment for this method says:

Creates, modifies, or deletes an environment variable stored in the current process .

How to set an user-wide or machine-wide environment variable in .NET Core-targeted app? Only a crossplatform solution makes sense (at least Windows and Linux).

Answer 1

For .NET Core 1.x it only allows setting an environment variable in the User context. With the new .NET Core 2.0 preview it allows using the EnvironmentVariableTarget . However, according to this GitHub issue setting User or Machine environment variables doesn't work on non-windows platforms.

Using other scopes (eg User, Machine) on non-Windows platforms) is not mapped in the implementation.

Also described in the GitHub issue is to use a workaround to check if it is a non-windows platform to set an environment variable. For example:

// omitting check for presence of bash binary
if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux)) System.Diagnostics.Process.Start("/bin/bash", "-c export " + variable + "=" + value);