Gets information about the system.
Posix requires that assumptions must not be made about the format of the values, e.g. the assumption that a release may contain three digits or anything else returned by this function.
Returns a hash of strings with information about the system. The indices of the hash are
domainname is a GNU extension and not part of POSIX.1, so this field is only available on GNU systems or when using the GNU libc.
The above example will output something similar to:
[sysname] => Linux
[nodename] => funbox
[release] => 2.6.20-15-server
[version] => #2 SMP Sun Apr 15 07:41:34 UTC 2007
[machine] => i686