How To Install WHMCS 6 on CentOS 7 cPanel
Upload and Unzip WHMCS 6
Step 1) Upload latest version of WHMCS to the server you want to host it on. I prefer to use SCP, but you can also upload the file via FTP or using cPanel's built in File Manager.
scp Downloads/whmcs_v602_full.zip root@$server_IP:/home/$cPanel_user/public_html/
Step 2) Unzip WHMCS on the server after it's been uploaded. Ideally you want to unzip this file while in /home/$cpanel_user/public_html/
cd /home/$cpanel_user/public_html/ unzip whmcs_v602_full.zip
Apply permissions and ownerships to WHMCS 6 files
Step 3) Apply proper ownership and permissions to the newly created "whmcs" directory
chown -R $cPanel_user. /home/$cpanel_user/public_html/whmcs/
Prepare for WHMCS 6 browser install
Step 4) rename "configuration.php.new" to "configuration.php", this file can be found under the main whmcs directory.
mv /home/$cpanel_user/public_html/whmcs/configuration.php.new /home/$cpanel_user/public_html/whmcs/configuration.php
Step 5) In cPanel, create a new database and database user to use for the WHMCS install process.
Begin WHMCS 6 install process
Step 6) Visit http://$your_domain/whmcs/install/install.php in a browser to begin the install process.
Step 7) Enter in database credentials that you used when creating the database in cpanel, then create an admin user with a SECURE password.
Post Install Cleanup
Step 8) After the install completes, remove the "/install/" directory, located under:
rm -rf /home/$cpanel_user/public_html/whmcs/install/
Step 9) Create crontab entry for the cpanel user that will run once a day at 12:01 AM
crontab -u $cPanel_user -e
Once the crontab editor is open, paste in this line, save the file and exit.
1 0 * * * php -q /home/$cPanel_user/public_html/whmcs/crons/cron.php >/dev/null 2>&1