1. The highest precedence goes to the value that has been defined in the environment (shell) by explicitly setting the value at the shell prompt.
2. The second-highest precedence goes to the value that has been defined in the private environment-configuration file in the home directory of the user (~/.informix).
3. The next-highest precedence goes to the value that has been defined in the common environment-configuration file ($INFORMIXDIR/etc/informix.rc).
4. The next highest precedence goes to the value that has been defined in your .login file.
5. The lowest precedence goes to the default value.
