Hi, our tool, Eggplant, might be overkill for an application like this, but it may be worth looking into if you can't find anything else. It can automate pretty much anything on any system. If the character based interface is really all you need to automate then I think there must be a number of ways to solve it, although none come immediately to mind. But if you'd like to integrate the automation of that application along with other processes on Unix, Windows, Mac or other systems then Eggplant might be just what you need.
I've just release a freeware tool, that allows you to do (li/u)nix command line testing. A simple scripting language based on shell is used to login to another server, execute one or more commands, check the exit status. Output is pulled to your central test server for further analysis.
Thank you all for your responses and appreciate that. Since I couldn't find a valid option with the given time I had to execute some manual test cases and do my testing.
However for phase 2 I need to perform a UI test where I need to validate each and every charter in the screen, against the previous version of the application. It seems unrealistic to do an eyeball test manually since the application itself consists of 100 odd screens.
So now again I need to automate these scenarios and my client demands for a free/open source solution.
As explained in the original post, the application is running on a HP-UX server where the end users use Putty as the front end tool.