resolveip

Resolve a hostname to an IP address

$ resolveip [example.org]

$ resolveip [1.1.1.1]

$ resolveip [[-s|--silent]] [example.org]

resolveip [OPTIONS] hostname_or_ip

hostname_or_ip
    The target string to resolve. This can be either a hostname (e.g., 'www.example.com') to be resolved into an IP address, or an IP address (e.g., '192.0.2.1') to be resolved into a hostname via a reverse DNS lookup.

-h, --help
    Displays a brief help message that outlines the command's usage and available options, then exits.

-v, --version
    Prints the version information of the resolveip utility to standard output and then exits.

resolveip is a minimalist command-line utility designed to perform simple DNS lookups, translating hostnames into their corresponding IP addresses and vice-versa. Unlike more feature-rich DNS tools like dig or nslookup, resolveip provides a straightforward interface, making it particularly useful for shell scripting or integration into other applications that require quick resolution without complex options.

This command is often found as part of the MySQL or MariaDB client packages, where it can be used internally by various database utilities to handle network address resolution. Its primary function is to print the resolved IP address or hostname to standard output, making it easy to capture and use the result programmatically. It leverages the system's underlying name service resolution mechanisms, including /etc/hosts and the configurations specified in /etc/resolv.conf, adhering to the Name Service Switch (NSS) settings.

Its simplicity means it lacks advanced features like specifying DNS servers, query types (e.g., MX, NS, PTR), or verbose debugging. It's intended for direct, single-lookup scenarios where a basic resolution is sufficient.

resolveip is not a universally available standard utility across all Linux distributions; it is most commonly distributed as part of the MySQL or MariaDB client packages. Users on systems without these packages might find it missing. For more advanced DNS queries or cross-distribution compatibility, alternatives like dig, host, or nslookup are generally preferred. It relies on the system's configured name resolution services and does not provide options to specify alternative DNS servers or network interfaces.

To resolve a hostname to an IP address:
resolveip www.google.com

To resolve an IP address to a hostname (reverse lookup):
resolveip 8.8.8.8

The command prints the resolved address or hostname to standard output.

resolveip typically outputs only the resolved IP address or hostname to standard output, followed by a newline character. If the resolution fails, it usually returns a non-zero exit code and may print an error message to standard error, depending on the version and underlying system libraries.

The resolveip utility's lineage is closely tied to the MySQL and MariaDB database systems. It was developed to serve as a simple, internal resolver for these database clients, facilitating tasks such as connecting to hosts by name or logging client IP addresses. Its design reflects the need for a lightweight and easily scriptable tool within that ecosystem, rather than a standalone, feature-rich DNS diagnostic utility. Over time, it has become a convenient, though specialized, command-line tool for basic resolution tasks for users who have the MySQL/MariaDB client tools installed.

dig(1), host(1), nslookup(1), getent(1), ping(8)