diff --git a/src/Composer/Installer/BinaryInstaller.php b/src/Composer/Installer/BinaryInstaller.php
index fb9f979eef7d..652b58ff1233 100644
--- a/src/Composer/Installer/BinaryInstaller.php
+++ b/src/Composer/Installer/BinaryInstaller.php
@@ -258,7 +258,7 @@ protected function generateUnixyProxyCode($bin, $link)
         $binContents = file_get_contents($bin);
         // For php files, we generate a PHP proxy instead of a shell one,
         // which allows calling the proxy with a custom php process
-        if (Preg::isMatch('{^(#!.*\r?\n)?<\?php}', $binContents, $match)) {
+        if (Preg::isMatch('{^(#!.*\r?\n)?[\r\n\t ]*<\?php}', $binContents, $match)) {
             // carry over the existing shebang if present, otherwise add our own
             $proxyCode = empty($match[1]) ? '#!/usr/bin/env php' : trim($match[1]);
             $binPathExported = $this->filesystem->findShortestPathCode($link, $bin, false, true);