list the softwares installed in Linux

I need list of 3rd party softwares installed in a Unix server (eg: Fedora / RedHat). I know if they are system supported format (like rpm format for fedora/redhat, pkg format for debian/ubuntu etc) we can list them by system specific commands ($ rpm -qa). But how to list the softwares installed like tar format, gunzip format etc?? Please give me some idea how I can get the list.

Sincerely waiting for your response.

Thank you very much,
Uday Kumar K

There is no easy way to do this apart from searching your system and looking in the places that they are likely to be found, e.g. /usr/someproduct, or /usr/local or /opt.

This is why it is a great advantage to find packaged software using the packaging tool of your operating system/distro rather than just install it manually. Obviously this isn't always possible, but if you are a disciplined administrator and always install software in logical locations then it shouldn't be too hard to keep track of.

A useful convention is to put stuff you have installed by hand in /opt or /usr/local and let the package management system completely reign over /usr/bin, /bin, /usr/sbin, etc.

Thanks Annihilannic & Era.