If it is a single file (e.g. config.php), the following is a base to start from:
Code:
cp /usr/local/cpanel/base/3rdparty/squirrelmail/config/config.php ~/squirrelmail_config.php
touch /var/cpanel/squirrelmail/install
chmod +x /var/cpanel/squirrelmail/install
vim /var/cpanel/squirrelmail/install
Contents of /var/cpanel/squirrelmail/install
Code:
#!/bin/sh
cp /root/squirrelmail_config.php /usr/local/cpanel/base/3rdparty/squirrelmail/config/config.php
chown cpanel:cpanel /usr/local/cpanel/base/3rdparty/squirrelmail/config/config.php
Customize the above to your particular needs.