I am searching for a automation testing tool which I can use for most of the UNIX platforms (AIX, Linux, HP UX, Solaris). The installation process of the application in all platforms is almost same. Are you aware of any automation tool (like WinRunner for Windows) to solve my problem?

I think an interactive testing can be done with the "expect" tool...Not sure if there are other good tools available.

Details of expect can be found here:
http://expect.nist.gov

There are many variations of expect that you can use depending on your needs, let us know what exacly you want to achieve. Otherwise, paid solution - load runner, or jmeter.

I am a QA Engineer. I have to test an application (functional testing) which runs on most of the UNIX platforms (solaris, linux, aix, hp ux). To test the functionalities of the application I need an automation tool where I can use in all unix platform.

Segue Extends SilkTest Functional Testing Support to Linux and UNIX Platforms | Business Wire | Find Articles at BNET

Please do more research on this tool and go through the tools specs to find more.

The best automation tool for Unix flavors is VITA from Veritas. VITA stands for Veritas Integrated Test Automation tool.

You need to edit the configuration file which includes adding the clustered
hosts, NFS client and servers, switch details and Storage Array details if any.

By providing all the necessary information, you can sit back and see how fast things work out for you. Its a very good tool for failover, loadbalancing, i/o fencing, Split-Brain testing to name a few.

The VITA tool is an excellent tool to automate provided, you give out the required inputs properly.