isql fails to run with "error while loading shared libraries: libncurses.so.4: cannot open shared object file: No such file or directory." What can I do?

You need libncurses.so.4.

Easysoft build the unixODBC Driver Manager with readline support using ncurses4 in an attempt to make it compatible with as many Linux distributions as possible. Some Linux distributions don't install compatibility libraries by default, and only include the latest library versions.

We have had this reported for Red Hat. Install ncurses4-5.0-9i386 or later from your Red Hat distribution.

Alternatively, build unixODBC yourself. Get the ncurses4 source distribution and build it yourself.