diff --git a/slic3r.pl b/slic3r.pl
index ed03c838a..c4d081989 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -124,6 +124,7 @@ die $@ if $@ && $opt{gui};
 if (@ARGV) {  # slicing from command line
     # apply command line config on top of default config
     my $config = Slic3r::Config->new_from_defaults;
+    $config->apply($_) for @external_configs;
     $config->apply($cli_config);
     $config->validate;