Host lookup that respects /etc/hosts

Utilities like host and dig let you see the IP address corresponding to the host name.

There is also the getent utility that can be used to query /etc/hosts or other NSS databases.

I am looking for a convenient standard utility (which is available in Debian, say) which resolves a host name regardless of where it is defined.

It should be more or less equivalent to

ping "$HOST" | head -1 | perl -lne '/((.*?))/ && print $1'

Answers:

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Method 1

If the problem is that you do not want to resolve these names using ipv6, then just ask getent to use ipv4 only. This will enumerate all ipv4 addresses:

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="3d5a54484e584d4d587d5f515c49495c">[email protected]</a>:~$ getent ahostsv4 www.google.com | cut -d' ' -f1 | sort -u
173.194.40.80
173.194.40.81
173.194.40.82
173.194.40.83
173.194.40.84

Method 2

The thing is there are several APIs to resolve host names like gethostbyname, getaddrinfo and inet_pton and some of those can return more than one address and/or you can query the type of address you want.

If you want a portable way to get one IPv4 address, then maybe:

perl -MSocket -le 'print inet_ntoa inet_aton shift' www.google.com

Method 3

The only command that I am aware that does what you want is resolveip:

http://linux.die.net/man/1/resolveip

However it only comes with mysql-server, which may not be ideal to install everywhere.

Method 4

gethostip -d name.domain from the syslinux package on Ubuntu (and probably Debian). -d outputs decimal format.

Method 5

(This answer only applies if you’re root on the machine.)

I used to be annoyed by this too, and then I standardized on running dnsmasq on all my machines. Dnsmasq is a lightweight DNS cache. As a side benefit, it serves the content of /etc/hosts over DNS.

Method 6

I used my pure perl knowledge and made a little script with error handling:

/usr/local/bin/gethostip:

#!/usr/bin/perl

# inspired by: https://unix.stackexchange.com/questions/71379/host-lookup-that-respects-etc-hosts#71393

use strict;
use Socket;

my $name = $ARGV[0];
if ($name eq '') {
  print STDERR "Usage: gethostip <hostname>n";
  exit 1;
}
my $ip = inet_aton($name);
die("Unable to resolve host name $name") if ($ip eq '');
my $ipstr = inet_ntoa($ip);
print "$ipstrn";

Thx to Stéphane Chazelas for the initial idea

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0