====== Wordpress Migration ======
Steps for Migrating Wordpress (WP) from a sub-domain to another sub-domain or main (www) domain.  In the explanation and example below we are migrating WP from live1.example.org sub-domain to example.org (or www.example.org) domain.  Overall there are 3 items to consider and change for the migration.  These are:
  * Database and/or Database Table Prefix
  * WP folder and files
  * Apache Web server configuration files

===== Identify Source and Target items/names =====
On migration from live1 to www, let's list all the items involved and what their new configuration/names would be.  When migrating from live1 to www, I am keeping in mind, that in future, we may do more migrations.  So I am naming the target components with different names (such as WP Table Prefix as dain1, WP folder as fain1, etc.) so it will be easier to migrate by component (or the entire website) in future to a different sub-domain or even another domain.

  * Items in Source (current live1 website)
    * MySQL WP Database and Database Table Prefix
    * WP folder and files
    * Web server (apache) WP sub-domain configuration
  * Target Names
    * Database (new) prefix is ''dain1'' - planning to use the same database with different table prefix
    * New WP Folder path is ''fain1''
    * Apache config file name is ''wain1'' - which will now point to ''www''

This will make it easy to search on items such as ''dain1'', ''fain1'', etc. to easily identify specific items and rename (replace) them for (future) migration.  If for example, if we //just// want to migrate the database to a different prefix, all we need to do is search everywhere for ''dain1'' and make sure it is configured correctly.  If we named everything the same (as I had before for ''live1''), then the task gets tedious to not simply search and replace, but also identify individual item types and make sure only the relevant items are changed.  For example a mass search and replace of ''live1'' everywhere (database, files, config) will not result in the correct setup as the new folder name may not be the target sub-domain of ''www''.

===== Backup =====
As is obvious, backup all of the existing source items - Web server files, MySQL database, Apache config.

==== Files ====
Backup files in ''/www/example.org/sub/live1'' where the current website files reside.  Your location may be different of course.

<code bash>
# Create a backup directory
mkdir -p /www/example.org/backups/01
# Change to that directory
cd /www/example.org/backups/01
# zip the files with recursive option to backup
zip -r live1.zip /www/example.org/sub/live1
</code>

==== Database ====
Backup WP database (named ''wordpress'') having tables prefixed with ''live1_''. 

=== Full ===
The below script backups all tables in the ''wordpress'' database.  This is good for backups, but not great for migration as we need only the ''live1'' prefix tables for migration.  Anyway, it's good to backup the entire database to be sure.

<code bash>
mysqldump --skip-extended-insert --skip-quick -uroot --password=XXXXX wordpress > wp.sql
</code>

=== By Table filter ===
For the purpose of migration, do a 2nd extract of just the ''live1_'' prefixed tables.  The other alternative is to edit the full backup extract above and delete everything //but// the ''live1_1'' SQLs.  However this may be a cleaner/simpler approach (in my opinion).  If your database already only has one set of tables, then this step is redundant.  Assuming you have other tables mixed in, in the same database, to extract //just// the tables starting with ''live1_'' in the ''wordpress'' database, 1st step would be to get the extract table list.  Then use that list as input to extract //only// the //live1// tables.  Once we have a script with just the ''live1'' tables we can start tinkering with the script to modify (search & replace) so the database content changes to point to ''www'' instead of ''live1''.  Assuming (again) your current database table prefix is ''live1'' you can do the following.

== Get table list first ==
We want to first get the list of tables with prefix ''live1_''.  So we can use this as input for the second dump command to //only// extract the live1_ tables.

<code bash>
mysql -uroot --password=XXXX -N information_schema -e "select table_name from tables where table_schema = 'wordpress' and table_name like 'live1_%'" > tables.txt
</code>
This will place the list of tables starting with ''live1_'' in the ''tables.txt'' file.

== Backup for selected tables ==
Using the above ''tables.txt'' as input, run this 2nd command to give you a clean extract of //just// the tables we need.
<code bash>
mysqldump --skip-extended-insert --skip-quick -uroot --password=XXXX wordpress `cat tables.txt` > wp_live1.sql
</code>

===== Steps to Migrate =====

==== Copy WP file ====
Copy existing live1 WP files (/www/example.org/sub/live1/main) to fain1 target folder (/www/example.org/fain1/main)
<code bash>
cd /www/example.org/fain1/main
cp -r sub/live1 .
</code>
Well, if you noticed, we did not even need to take a backup of the current (live1) folder!  We are not going to mess with the source anyway and just creating a new folder for the new website.  But again, backups are a good thing because one wrong key stroke and you can erase the wrong folder.  Same goes for database backup too.

==== Backup (Copy) SQL file ====
Save Original to new file just so it's easy to come back to a starting point without having to export the database again, if you mess up the migration.
<code bash>
cp wp_live1.sql wp_dain1.sql
</code>

==== Rename folder in database script ====
The data inside the WP database has hard-coded references to the folder in which the install was residing.  So this 1st step takes care of searching and replacing all of those folder references.

from: \\
''/www/example.org/sub/live1/main''

to: \\
''/www/example.org/fain1/main''

The command to do that is:
<code bash>
sed -i s#/www/example.org/sub/live1/main#/www/example.org/fain1/main#g wp_dain1.sql
</code>

==== Change subdomain in database script ====
Rename HTTP prefix subdomain from live1 to  ____  (blank or www).  Again, the URL to the site is //also// hard-coded inside WP.  So let's replace those as well.

<code bash>
sed -i s#live1.example.org#example.org#g wp_dain1.sql
</code>

Note: It may be a good idea to append http to the search and replace options if you http address coincides with your folder address. Although again, this may not be an issue since we already completed the folder adjustment 1st.  Do a quick check (search only) to make sure nothing that should not be changed is getting changed.  

==== Database prefix ====
Rename Database prefix from live1 to dain1. **SKIP THIS STEP for an alternative approach**.  It is here as a more cautious approach to search/replace items in the database script.  At this point you should be able to do a plain / full search and replace of all remaining instances of ''live1'' in step below. 

<code bash>
sed -i s#^INSERT\ INTO\ \`live1_#INSERT\ INTO\ \`dain1_# wp_dain1.sql
sed -i s#^CREATE\ TABLE\ \`live1_#CREATE\ TABLE\ \`dain1_# wp_dain1.sql
sed -i s#^DROP\ TABLE\ IF\ EXISTS\ \`live1_#DROP\ TABLE\ IF\ EXISTS\ \`dain1_# wp_dain1.sql
sed -i s#^LOCK\ TABLES\ \`live1_#LOCK\ TABLES\ \`dain1_# wp_dain1.sql
sed -i s#40000\ ALTER\ TABLE\ \`live1_#40000\ ALTER\ TABLE\ \`dain1_# wp_dain1.sql
etc.
</code>


==== Update remaining live1 to dain1 ==== 
Update rest of ''live1_'' to ''dain1_'' in SQL file.

<code bash>
sed -i s/live1_/dain1_/g wp_dain1.sql
</code>

==== Final SQL file check ====
Search for ''live1'' anywhere else in SQL file to be sure.  Note: Search does not include underscore after ''live1'' so it may find hits that are ignorable.
<code bash>
grep live1 wp_dain1.sql
</code>
Take note of results and made final edits if required.

==== Database prefix in config ====
Update ''wp-config.php'' with table prefix dain1 from live1
<code php>
$table_prefix  = 'dain1_';
</code>


==== Changing Unique Keys and Salts ====
Also update ''wp-config.php'''s KEYs using the https://api.wordpress.org/secret-key/1.1/salt/ WordPress.org secret-key service link and replace them in config.php.  Below is a sample replacement. Please generate your own!

<code php>
define('AUTH_KEY',         'AS6GbR*uPvXjso&HCq}.gqZ?Z|5:1{|DiD=vv7+3IwshUKw:uafn5JpF?- >}0qm');
define('SECURE_AUTH_KEY',  'd#&lFT)]4+?J}#ocQ`g8+P:o68H?~d]#+qo5%3uI-6irrF%-XOpz`6?IWd*`E@GE');
define('LOGGED_IN_KEY',    '.mWpq^5R28Z#|(<~V7CYVwb}u&-vR)Rv@CTe;0SKrCAJY rdC!@bFtk*a[ [T`z7');
define('NONCE_KEY',        'EK-#+k|HbBf?#)_O P#,A#03:#kKw![GG#z^/Y+0w4?Owiz<g.+t)[JMsB Mu&#z');
define('AUTH_SALT',        'iXL!G!T:G%ss<L9wACbgDGnPO|-d^f{3F,|w6F!a,fz|@er/aX+)RS~t&)-M+g2|');
define('SECURE_AUTH_SALT', 'Io%h|}zz((P$cCq6-ug+W.e-~}eMev}2 sKc7G4jS|z+ d;fEjd~0XdIuqOg6>M2');
define('LOGGED_IN_SALT',   'K@17hA> Idi13%{9pF$SmjB1u:N&N5OsW2~OQ&RSI|>aCpeu0G#)B]G_>4 x|>h7');
define('NONCE_SALT',       ' u}U0wSwoi]ErDQq ncxvY(M+*p*TR7}gk0:Nyfc4n Q8hV<EuglA|S*MW.oRiD[');
</code>
==== Create Tables ====
Run ''wp_dain1.sql'' to create the new set of tables tables on the ''wordpress'' database.
<code> 
mysql -uroot --password=XXXXX wordpress < wp_dain1.sql
</code>
==== Apache config ====
  * Change apache config for new website (www or whatever it is) to point to the new filesystem folder
  * Update/Copy ''htpasswd'' file for new website if any for admin/ssl authentication
  * Validate Web server has permissions on the new/copied file folders.
  * Restart (or reload) Web server for configuration to take effect
  * Enable any redirection that may be required so any bookmarked ''live1'' site is redirected

===== Test =====
Of course test the migrated website and it's possible few tweaks are required through the Administrative login.  Make sure old cookies if any are cleared in your browser.