Recently we needed to change a multisite main domain for a large website. We concluded that we need to change code in 5 places as follow:

• wp_options table and wp_#_options tables: options named “siteurl” and “home” ;
• wp_site table ;
• wp_sitemeta: the option named “siteurl” ;
• wp_blogs: any entries in the “domains” column that have the old domain name ;
• wp-config.php file.

So here are the steps we had made in order to change primary domain for a wordpress multisite:

     1. Backup your mysql database ;
     2. Export the theme settings if you have that option ;
     3. Create a temporary directory where you will dump the data ;
     4. Save the following script in temporary directory ;

#!/bin/bash

#get all tables contain name options
for i in `mysql -u user -p'password' dbname -e "show tables;" | grep options`;
do
mysqldump -u user -p'password' dbname --skip-add-drop-table --no-create-info --replace  $i --where="option_name='siteurl' or option_name='home'" > $i
done
mysqldump -u user -p'password' dbname --skip-add-drop-table --no-create-info --replace wp_site > wp_site
mysqldump -u user -p'password' dbname --skip-add-drop-table --no-create-info --replace wp_blogs > wp_blogs
mysqldump -u user -p'password' dbname --skip-add-drop-table --no-create-info --replace wp_sitemeta > wp_sitemeta


#replace domain in dump tables
for i in `ls | grep wp`
do
sed -i 's#old-domain.com#new-domain.com#g' $i
done

#reimport data
for i in `ls | grep wp`
do
mysql -u user -p'password' dbname < $i
done

      5. Change the values of user, password, dbname, old-domain.com, new-domain.com with your values and execute it (if your tables names are custom change with correct ones.) ;
     6. Change the values in your wp-config.php file ;

define('WP_SITEURL', 'http://new-domain.com');
define('WP_HOME', 'http://new-domain.com');
define('DOMAIN_CURRENT_SITE', 'new-domain.com');

      7.  Adjust apache/nginx config  to reflect new domain name ;
      8.  Login as admin and import theme settings ;
      9.  Adjust the values in theme options if there any (usally the logo path, favicon path, etc.) ;
      10.  Empty cache if any.

Now everything should work with the new domain name.

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