diff --git a/src/Composer/Command/SelfUpdateCommand.php b/src/Composer/Command/SelfUpdateCommand.php
index 78b27460e..226aafeb5 100644
--- a/src/Composer/Command/SelfUpdateCommand.php
+++ b/src/Composer/Command/SelfUpdateCommand.php
@@ -351,6 +351,10 @@ TAGSPUBKEY
                 @copy($localFilename, $backupTarget);
             }
 
+            if ($targetFilename = getenv('COMPOSER_SELF_UPDATE_TARGET')) {
+                $localFilename = realpath($targetFilename) ?: $targetFilename;
+            }
+
             rename($newFilename, $localFilename);
 
             return null;