Determine OS and list of installed packages via SSH login

This script will, if given a userid/password or key to the remote system, login to that system, determine the OS it is running, and for supported systems, extract the list of installed packages/rpms.

The ssh protocol is used to log in. If a specific port is configured for the credential, then only this port will be tried. Else any port that offers ssh, usually port 22. Upon successful login, the command 'uname -a' is issued to find out about the type and version of the operating system. The result is analysed for various patterns and in several cases additional commands are tried to find out more details and to confirm a detection. The regular Linux distributions are detected this way as well as other unixoid systems and also many Linux-based devices and appliances. If the system offers a package database, for example RPM- or DEB-based, this full list of installed packages is retrieved for further patch-level checks.