Ive been playing around with Firebird and isql. I noticed it has the 'shell' command. However this shell drops you to a sub-process on the local system regardless if your connected to a remote DB. Is it possible to run system level commands on Firebird on the system hosting the DB? Google seems to be useless with regards to Firebird, I have read the documentation for Firebird too and dont see any mention of it.
The only way to do it is to write UDF function (in such languages like Delphi or C/C++). But even if you write or find such a function, its usefulness may be limited because Firebird can run under special user account with limited rights.