System$getHostname: Retrieves the computer name of the current host
Description
 Retrieves the computer name of the current host.
Usage
## Static method (use this):
## System$getHostname(...)
## Don't use the below:
"getHostname"(static, ...)
Details
 First, this function checks the system environment variables HOST,
 HOSTNAME, and COMPUTERNAME.
 Second, it checks Sys.info()["nodename"] for host name details.
 Finally, it tries to query the system command uname -n.