diff --git a/src/shell.js b/src/shell.js
index e9306aa6c..9aae7e476 100644
--- a/src/shell.js
+++ b/src/shell.js
@@ -27,7 +27,7 @@ async function execArgs(tag, file, args, options) {
     assert(Array.isArray(args));
     assert.strictEqual(typeof options, 'object');
 
-    debug(`${tag} exec: ${file} ${JSON.stringify(args)}`);
+    debug(`${tag} execArgs: ${file} ${JSON.stringify(args)}`);
 
     const execOptions = Object.assign({ encoding: 'utf8', shell: false }, options);
 
@@ -56,9 +56,31 @@ async function exec(tag, cmd, options) {
     assert.strictEqual(typeof cmd, 'string');
     assert.strictEqual(typeof options, 'object');
 
-    cmd = options.shell ? cmd : cmd.replace(/\s+/g, ' '); // collapse spaces when not using shell. note: no more complexity like parsing quotes here!
-    const [file, ...args] = cmd.split(' ');
-    return await execArgs(tag, file, args, options);
+    if (!options.shell) {
+        cmd = cmd.replace(/\s+/g, ' '); // collapse spaces when not using shell. note: no more complexity like parsing quotes here!
+        const [file, ...args] = cmd.split(' ');
+        return await execArgs(tag, file, args, options);
+    }
+
+    debug(`${tag} exec: ${cmd}`);
+
+    return new Promise((resolve, reject) => {
+        const cp = child_process.exec(cmd, options, function (error, stdout, stderr) {
+            if (!error) return resolve(stdout);
+
+            const e = new BoxError(BoxError.SHELL_ERROR, `${tag} errored with code ${error.code} message ${error.message}`);
+            e.stdout = stdout; // when promisified, this is the way to get stdout
+            e.stderr = stderr; // when promisified, this is the way to get stderr
+            debug(`${tag}: ${cmd} errored`, error);
+            reject(e);
+        });
+
+        // https://github.com/nodejs/node/issues/25231
+        if (options.input) {
+            cp.stdin.write(options.input);
+            cp.stdin.end();
+        }
+    });
 }
 
 function sudo(tag, args, options, callback) {