--- loncom/debugging_tools/modify_config_files.pl	2021/03/13 19:38:32	1.18
+++ loncom/debugging_tools/modify_config_files.pl	2021/03/25 13:23:07	1.20
@@ -2,7 +2,7 @@
 #
 # The LearningOnline Network
 #
-# $Id: modify_config_files.pl,v 1.18 2021/03/13 19:38:32 raeburn Exp $
+# $Id: modify_config_files.pl,v 1.20 2021/03/25 13:23:07 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -244,11 +244,30 @@ if ($dist =~ /^fedora(\d+)$/) {
     }
 }
 
-my $mysql_global_status =
-    &update_file('/etc/my.cnf',
-             [{section =>'mysqld',
-               key     =>'wait_timeout=',
-               value   =>'31536000', }]);
+my $mysqlfile = '/etc/my.cnf';
+my $mysqlconf = [{section =>'mysqld',
+                  key     =>'wait_timeout=',
+                  value   =>'31536000'}];
+if ($dist =~ /^ubuntu(\d+)$/) {
+    my $version = $1;
+    $mysqlfile = '/etc/mysql/my.cnf';
+    if ($version > 14) {
+        $mysqlfile = '/etc/mysql/mysql.conf.d/mysqld.cnf';
+        if ($version < 20) {
+            push(@{$mysqlconf},
+                 {section =>'mysqld',
+                  key     =>'sql_mode=',
+                  value   =>'"STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"'});
+        } else {
+            push(@{$mysqlconf},
+                 {section =>'mysqld',
+                  key     =>'sql_mode=',
+                  value   =>'"STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION"'});
+        }
+    }
+}
+
+my $mysql_global_status = &update_file($mysqlfile,$mysqlconf);
 
 my $local_my_cnf = '/home/www/.my.cnf';
 if (! -e $local_my_cnf) {