Validate Hostname or Scan hostname

Hi Experts,

I would like to know better way to validate the Hostname or Scan Hostname(RAC) when user enter the hostname as part of my script.

I know "nslookup" or "ping" are available option, however, just curious to check whether any better way to validate.

Need to write small script to validate the hostname given by user to ensure that it accepts only valid hostname/scan hostname.

Also, I wonder, whether we have any option to store & hide LDAP user password temporarily to avoid user to provide password multiple times

Please share your ideas n suggestions here, it would be much appreciated