How to set up I-SQL?

Documentation for the install and setup process is limited.

There are a few parts needed to enable use of I-SQL with IBM Informix Dynamic Server.

1. Set the INFORMIXDIR environment variable to the path where you are installing I-SQL. This should be a separate directory from the database server software.
2. Install the I-SQL software.
3. To use the I-SQL software, set the following environment variables:
   INFORMIXSERVER= your database instance
   INFORMIXSQLHOSTS = the full path to your sqlhosts file.
   PATH = $INFORMIXDIR/bin:/other_paths...

(note that isql is a generic command file on some operating systems. Make sure the Informix/bin reference is first.)

A library path is needed also. The variable to use will depend on your Operating System, usually:

LD_LIBRARY_PATH = <INFORMIXDIR>/lib:<INFORMIXDIR>/lib/tools:<INFORMIXDIR>/lib/esql

for AIX or HP-UX:
SHLIB_PATH = <INFORMIXDIR>/lib:<INFORMIXDIR>/lib/tools:<INFORMIXDIR>/lib/esql