diff --git a/services/service.ts b/services/service.ts
index 40b1541..4620517 100644
--- a/services/service.ts
+++ b/services/service.ts
@@ -39,6 +39,18 @@ const homebrewBaseDir = ((): string | null => {
   }
 })();
 
+const nodeVersion = (() => {
+  try {
+    // Just in case there's a build/pre-release suffix.
+    const core = process.versions.node.split(/[-+]/, 1)[0] as string;
+    const [major, minor = 0, patch = 0] = core.split('.').map((x) => parseInt(x, 10));
+    return { major, minor, patch };
+  } catch (err) {
+    console.warn('getting nodeVersion failed:', err);
+    return { major: 0, minor: 0, patch: 0 };
+  }
+})();
+
 // Maps internal setting field name with filesystem flag name.
 type FlagName = string;
 const availableFlags = {
@@ -605,9 +617,20 @@ function runService() {
    * Executes a shell command and responds with exit code, stdout and stderr.
    */
   type ExecPayload = { command: string };
-  service.register('exec', (message) => {
+  service.register('exec', (message: Message) => {
+    if (!('command' in message.payload)) {
+      message.respond(makeError('missing "command"'));
+      return;
+    } else if (typeof message.payload['command'] !== 'string') {
+      message.respond(makeError('"command" is not a string'));
+      return;
+    }
+
     const payload = message.payload as ExecPayload;
-    child_process.exec(payload.command, { encoding: 'buffer' }, (error, stdout, stderr) => {
+
+    const encoding = nodeVersion.major === 0 && nodeVersion.minor < 12 ? null : 'buffer';
+
+    child_process.exec(payload.command, { encoding }, (error, stdout, stderr) => {
       const response = {
         error,
         stdoutString: stdout.toString(),
@@ -629,7 +652,7 @@ function runService() {
   service.register('spawn', (message) => {
     const payload = message.payload as ExecPayload;
     const respond = (event: string, args: Record<string, any>) => message.respond({ event, ...args });
-    const proc = child_process.spawn('/bin/sh', ['-c', payload.command]);
+    const proc = child_process.spawn('/bin/sh', ['-c', '--', payload.command]);
     proc.stdout.on('data', (data) =>
       respond('stdoutData', {
         stdoutString: data.toString(),