diff --git a/src/Composer/Command/ConfigCommand.php b/src/Composer/Command/ConfigCommand.php
index 1761402ee..eb7a3ff1f 100644
--- a/src/Composer/Command/ConfigCommand.php
+++ b/src/Composer/Command/ConfigCommand.php
@@ -146,10 +146,14 @@ EOT
         // passed in a file to use
         $configFile = $input->getOption('global')
             ? ($this->config->get('home') . '/config.json')
-            : ($input->getOption('file') ?: trim(getenv('COMPOSER')) ?: 'composer.json');
+            : ($input->getOption('file') ?: Factory::getComposerFile());
 
         // Create global composer.json if this was invoked using `composer global config`
-        if ($configFile === 'composer.json' && !file_exists($configFile) && realpath(getcwd()) === realpath($this->config->get('home'))) {
+        if (
+            ($configFile === 'composer.json' || $configFile === './composer.json')
+            && !file_exists($configFile)
+            && realpath(getcwd()) === realpath($this->config->get('home'))
+        ) {
             file_put_contents($configFile, "{\n}\n");
         }
 
diff --git a/src/Composer/Console/Application.php b/src/Composer/Console/Application.php
index 96ba7d900..081476d93 100644
--- a/src/Composer/Console/Application.php
+++ b/src/Composer/Console/Application.php
@@ -127,13 +127,13 @@ class Application extends BaseApplication
         }
 
         // prompt user for dir change if no composer.json is present in current dir
-        if ($io->isInteractive() && !in_array($commandName, array('init', 'about', 'help', 'diagnose', 'self-update', 'global'), true) && !file_exists('./composer.json')) {
+        if ($io->isInteractive() && !in_array($commandName, array('init', 'about', 'help', 'diagnose', 'self-update', 'global'), true) && !file_exists(Factory::getComposerFile())) {
             $dir = dirname(getcwd());
             $home = realpath(getenv('HOME') ?: getenv('USERPROFILE') ?: '/');
 
             // abort when we reach the home dir or top of the filesystem
             while (dirname($dir) !== $dir && $dir !== $home) {
-                if (file_exists($dir.'/composer.json')) {
+                if (file_exists($dir.'/'.Factory::getComposerFile())) {
                     if ($io->askConfirmation('<info>No composer.json in current directory, do you want to use the one at '.$dir.'?</info> [<comment>Y,n</comment>]? ', true)) {
                         $oldWorkingDir = getcwd();
                         chdir($dir);