By default, my isql-fb (FreeBSD) doesn't save a history file. I started using FB over a decade ago & have never seen persistent history in isql, so I assumed that it's not a feature.
Today, I found that there is a function in isql.cpp viz:
// Save SQL command (not isql's own commands) to a history file only if we
// are in interactive mode.
"void InputDevices::saveCommand(const char* statement, const char* term)"
if (m_ifp.indev_fpointer == stdin)
FILE* f = m_ofp.indev_fpointer;
// Add newline to make the file more readable.
Command* command = new Command(statement, term);
I have not been able to determine how the file handle m_ofp.indev_fpointer gets initialized, Presumably it is meant to already have opened the history file. Maybe there is code missing for this.
FWIW, MS Windows users have ' IDS_DEF_HIST_FILE, "Unable to create default command history file %s"' (isql.rc) as a possible error.
Now, it looks suspiciously like there is intent in isql-fb to manage persistent command history that doesn't work.