diff --git a/dist/env-cmd.js b/dist/env-cmd.js
index e02865f..a99077e 100644
--- a/dist/env-cmd.js
+++ b/dist/env-cmd.js
@@ -33,11 +33,15 @@ export async function EnvCmd({ command, commandArgs, envFile, rc, options = {},
         command = expandEnvs(command, env);
         commandArgs = commandArgs.map(arg => expandEnvs(arg, env));
     }
+    if (!command) {
+        throw new Error('env-cmd cannot be used as a standalone command. ' +
+            'Refer to the documentation for usage examples: https://npm.im/env-cmd');
+    }
     // Execute the command with the given environment variables
     const proc = spawn(command, commandArgs, {
         stdio: 'inherit',
         shell: options.useShell,
-        env: env,
+        env,
     });
     // Handle any termination signals for parent and child proceses
     const signals = new TermSignals({ verbose: options.verbose });
diff --git a/dist/parse-args.js b/dist/parse-args.js
index 4c7a632..1af336a 100644
--- a/dist/parse-args.js
+++ b/dist/parse-args.js
@@ -94,5 +94,6 @@ export function parseArgsUsingCommander(args) {
         .option('--use-shell', 'Execute the command in a new shell with the given environment')
         .option('--verbose', 'Print helpful debugging information')
         .allowUnknownOption(true)
+        .allowExcessArguments(true)
         .parse(['_', '_', ...args], { from: 'node' });
 }
diff --git a/dist/parse-env-file.d.ts b/dist/parse-env-file.d.ts
index 299c2f9..b5661c6 100644
--- a/dist/parse-env-file.d.ts
+++ b/dist/parse-env-file.d.ts
@@ -19,3 +19,12 @@ export declare function stripComments(envString: string): string;
  * Strips out newlines from env file string
  */
 export declare function stripEmptyLines(envString: string): string;
+/**
+ * If we load data from a file like .js, the user
+ * might export something which is not an object.
+ *
+ * This function ensures that the input is valid,
+ * and converts the object's values to strings, for
+ * consistincy. See issue #125 for details.
+ */
+export declare function normalizeEnvObject(input: unknown, absolutePath: string): Environment;
diff --git a/dist/parse-env-file.js b/dist/parse-env-file.js
index 00e3cc8..1d430ab 100644
--- a/dist/parse-env-file.js
+++ b/dist/parse-env-file.js
@@ -14,7 +14,7 @@ export async function getEnvFileVars(envFilePath) {
     }
     // Get the file extension
     const ext = extname(absolutePath).toLowerCase();
-    let env = {};
+    let env;
     if (IMPORT_HOOK_EXTENSIONS.includes(ext)) {
         // For some reason in ES Modules, only JSON file types need to be specifically delinated when importing them
         let attributeTypes = {};
@@ -22,7 +22,7 @@ export async function getEnvFileVars(envFilePath) {
             attributeTypes = { [importAttributesKeyword]: { type: 'json' } };
         }
         const res = await import(pathToFileURL(absolutePath).href, attributeTypes);
-        if ('default' in res) {
+        if (typeof res === 'object' && res && 'default' in res) {
             env = res.default;
         }
         else {
@@ -32,12 +32,14 @@ export async function getEnvFileVars(envFilePath) {
         if (isPromise(env)) {
             env = await env;
         }
+        return normalizeEnvObject(env, absolutePath);
     }
-    else {
-        const file = readFileSync(absolutePath, { encoding: 'utf8' });
-        env = parseEnvString(file);
+    const file = readFileSync(absolutePath, { encoding: 'utf8' });
+    switch (ext) {
+        // other loaders can be added here
+        default:
+            return parseEnvString(file);
     }
-    return env;
 }
 /**
  * Parse out all env vars from a given env file string and return an object
@@ -61,23 +63,18 @@ export function parseEnvVars(envString) {
         // Note: match[1] is the full env=var line
         const key = match[2].trim();
         let value = match[3].trim();
-        // remove any surrounding quotes
-        value = value
-            .replace(/(^['"]|['"]$)/g, '')
-            .replace(/\\n/g, '\n');
-        // Convert string to JS type if appropriate
-        if (value !== '' && !isNaN(+value)) {
-            matches[key] = +value;
-        }
-        else if (value === 'true') {
-            matches[key] = true;
-        }
-        else if (value === 'false') {
-            matches[key] = false;
+        // if the string is quoted, remove everything after the final
+        // quote. This implicitly removes inline comments.
+        if (value.startsWith("'") || value.startsWith('"')) {
+            value = value.slice(1, value.lastIndexOf(value[0]));
         }
         else {
-            matches[key] = value;
+            // if the string is not quoted, we need to explicitly remove
+            // inline comments.
+            value = value.split('#')[0].trim();
         }
+        value = value.replace(/\\n/g, '\n');
+        matches[key] = value;
     }
     return JSON.parse(JSON.stringify(matches));
 }
@@ -95,3 +92,25 @@ export function stripEmptyLines(envString) {
     const emptyLinesRegex = /(^\n)/gim;
     return envString.replace(emptyLinesRegex, '');
 }
+/**
+ * If we load data from a file like .js, the user
+ * might export something which is not an object.
+ *
+ * This function ensures that the input is valid,
+ * and converts the object's values to strings, for
+ * consistincy. See issue #125 for details.
+ */
+export function normalizeEnvObject(input, absolutePath) {
+    if (typeof input !== 'object' || !input) {
+        throw new Error(`env-cmd cannot load “${absolutePath}” because it does not export an object.`);
+    }
+    const env = {};
+    for (const [key, value] of Object.entries(input)) {
+        // we're intentionally stringifying the value here, to
+        // match what `child_process.spawn` does when loading 
+        // env variables.
+        // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
+        env[key] = `${value}`;
+    }
+    return env;
+}
diff --git a/dist/types.d.ts b/dist/types.d.ts
index 92f1ba3..483442f 100644
--- a/dist/types.d.ts
+++ b/dist/types.d.ts
@@ -1,5 +1,5 @@
 import type { Command } from '@commander-js/extra-typings';
-export type Environment = Partial<Record<string, string | number | boolean>>;
+export type Environment = Partial<Record<string, string>>;
 export type RCEnvironment = Partial<Record<string, Environment>>;
 export type CommanderOptions = Command<[], {
     environments?: true | string[];
diff --git a/package.json b/package.json
index 5a514bd..62db792 100644
--- a/package.json
+++ b/package.json
@@ -49,8 +49,8 @@
   },
   "homepage": "https://github.com/toddbluhm/env-cmd#readme",
   "dependencies": {
-    "@commander-js/extra-typings": "^12.1.0",
-    "commander": "^12.1.0",
+    "@commander-js/extra-typings": "^13.1.0",
+    "commander": "^13.1.0",
     "cross-spawn": "^7.0.6"
   },
   "devDependencies": {
diff --git a/src/parse-args.ts b/src/parse-args.ts
index 8f0120c..03fbad4 100644
--- a/src/parse-args.ts
+++ b/src/parse-args.ts
@@ -108,5 +108,6 @@ export function parseArgsUsingCommander(args: string[]): CommanderOptions {
     .option('--use-shell', 'Execute the command in a new shell with the given environment')
     .option('--verbose', 'Print helpful debugging information')
     .allowUnknownOption(true)
+    .allowExcessArguments(true)
     .parse(['_', '_', ...args], { from: 'node' })
 }