Slugify cache prefix and quote it in the env

app/Services/Installer/ConfigService.php

@@ -212,7 +212,8 @@ class ConfigService extends Service
     protected function configCacheDriver($opts)
     {
         // Set the cache prefix
-        $opts['CACHE_PREFIX'] = uniqid($opts['SITE_NAME'].'_');
+        $prefix = substr(str_slug($opts['SITE_NAME'], '_'), 0, 8);
+        $opts['CACHE_PREFIX'] = strtolower(uniqid($prefix.'_'));
 
         // Figure out what cache driver to initially use, depending on
         // what is installed. It won't detect redis or anything, though

resources/stubs/installer/env.stub

@@ -34,7 +34,7 @@ DB_SOCKET=
 
 # CACHE SETTINGS
 CACHE_DRIVER=$CACHE_DRIVER$
-CACHE_PREFIX=$CACHE_PREFIX$
+CACHE_PREFIX='$CACHE_PREFIX$'
 
 # EMAIL SETTINGS
 # Look at the available mail configs in config/mail.php