> In the Firebird migration pros and cons Document provided on the
> Firebirdsql internet side there is a text passage that says that there
> are Add-ons available for native full text search with Firebird.
>
> I want to use Firebird 1.5.2 on a Linux machine.
> Where can I find those Add-ons and does an Add-on for native full text
> searching really exists for Linux?

AFAIK currently there is not any add-on
-that would add _native_ fulltext capabilities (i.e. as part of SQL), nor
-that would run on Linux, nor
-that would be free

Your choices are
- use LIKE/CONTAINING, which is good for small databases
(hundreds of documents)
- write something yourself (create suitable tables for holding fulltext index
data, write routines for filling it and for constructing queries)
- use some external fulltext engine (then you will have problems with keeping
everytihg synchronized and with combining data from two separate systems)
- the add-ons for Firebird I know of are
* FTS components for IBObjects (it requires Delphi clinet)
* FastTextSearch (it requires Win32 server)
* my own fulltext system (currently for Win32 server, but port to Linux will be easy)
(designed to achieve good speed even with complex queries on millions
indexed documents)

Ivan
http://www.volny.cz/iprenosil/interbase/