src/vs/platform/shell/node/shellEnv.ts/doResolveUnixShellEnv
async function doResolveUnixShellEnv(logService: ILogService, token: CancellationToken): Promise<typeof process.env> {
	const runAsNode = process.env['ELECTRON_RUN_AS_NODE'];
	logService.trace('getUnixShellEnvironment#runAsNode', runAsNode);

	const noAttach = process.env['ELECTRON_NO_ATTACH_CONSOLE'];
	logService.trace('getUnixShellEnvironment#noAttach', noAttach);

	const mark = generateUuid().replace(/-/g, '').substr(0, 12);
	const regex = new RegExp(mark + '(.*)' + mark);

	const env = {
		...process.env,
		ELECTRON_RUN_AS_NODE: '1',
		ELECTRON_NO_ATTACH_CONSOLE: '1'
	};

	logService.trace('getUnixShellEnvironment#env', env);
	const systemShellUnix = await getSystemShell(OS, env);
	logService.trace('getUnixShellEnvironment#shell', systemShellUnix);

	return new Promise<typeof process.env>((resolve, reject) => {
		if (token.isCancellationRequested) {
			return reject(canceled());
		}

		// handle popular non-POSIX shells
		const name = basename(systemShellUnix);
		let command: string, shellArgs: Array<string>;
		const extraArgs = (process.versions['electron'] && process.versions['microsoft-build']) ? '--ms-enable-electron-run-as-node' : '';
		if (/^pwsh(-preview)?$/.test(name)) {
			// Older versions of PowerShell removes double quotes sometimes so we use "double single quotes" which is how
			// you escape single quotes inside of a single quoted string.
			command = `& '${process.execPath}' ${extraArgs} -p '''${mark}'' + JSON.stringify(process.env) + ''${mark}'''`;
			shellArgs = ['-Login', '-Command'];
		} else {
			command = `'${process.execPath}' ${extraArgs} -p '"${mark}" + JSON.stringify(process.env) + "${mark}"'`;

			if (name === 'tcsh') {
				shellArgs = ['-ic'];
			} else {
				shellArgs = ['-ilc'];
			}
		}

		logService.trace('getUnixShellEnvironment#spawn', JSON.stringify(shellArgs), command);

		const child = spawn(systemShellUnix, [...shellArgs, command], {
			detached: true,
			stdio: ['ignore', 'pipe', 'pipe'],
			env
		});

		token.onCancellationRequested(() => {
			child.kill();

			return reject(canceled());
		});

		child.on('error', err => {
			logService.error('getUnixShellEnvironment#errorChildProcess', toErrorMessage(err));
			reject(err);
		});

		const buffers: Buffer[] = [];
		child.stdout.on('data', b => buffers.push(b));

		const stderr: Buffer[] = [];
		child.stderr.on('data', b => stderr.push(b));

		child.on('close', (code, signal) => {
			const raw = Buffer.concat(buffers).toString('utf8');
			logService.trace('getUnixShellEnvironment#raw', raw);

			const stderrStr = Buffer.concat(stderr).toString('utf8');
			if (stderrStr.trim()) {
				logService.trace('getUnixShellEnvironment#stderr', stderrStr);
			}

			if (code || signal) {
				return reject(new Error(localize('resolveShellEnvExitError', "Unexpected exit code from spawned shell (code {0}, signal {1})", code, signal)));
			}

			const match = regex.exec(raw);
			const rawStripped = match ? match[1] : '{}';

			try {
				const env = JSON.parse(rawStripped);

				if (runAsNode) {
					env['ELECTRON_RUN_AS_NODE'] = runAsNode;
				} else {
					delete env['ELECTRON_RUN_AS_NODE'];
				}

				if (noAttach) {
					env['ELECTRON_NO_ATTACH_CONSOLE'] = noAttach;
				} else {
					delete env['ELECTRON_NO_ATTACH_CONSOLE'];
				}

				// https://github.com/microsoft/vscode/issues/22593#issuecomment-336050758
				delete env['XDG_RUNTIME_DIR'];

				logService.trace('getUnixShellEnvironment#result', env);
				resolve(env);
			} catch (err) {
				logService.error('getUnixShellEnvironment#errorCaught', toErrorMessage(err));
				reject(err);
			}
		});
	});
}