What command would you use to test a hostname in Linux?

The command used to test a hostname in Linux is host. This command is specifically designed to perform DNS lookups, providing a way to query DNS servers for information about a specific hostname or IP address. When you enter a hostname with the host command, it will return the IP address associated with that hostname, helping you confirm whether the hostname resolves correctly to an IP address.

The command ping is commonly used to check the reachability of a host on a network and can also resolve hostnames to IP addresses, but it primarily focuses on testing connectivity rather than purely determining DNS resolution.

Similarly, nslookup is another tool for querying DNS information and can be used to test hostnames, but it is considered somewhat less user-friendly and more obsolete compared to the host command.

Lastly, traceroute is a tool used to trace the path packets take from one host to another across a network, primarily to diagnose routing issues, rather than to test hostname resolution directly.

Thus, the host command is the most appropriate choice for explicitly testing a hostname in a straightforward manner, focusing on DNS resolution.