output of hostname -A

luofeiyu · 03-03-2017, 07:16 PM

`hostname -A` displays all FQDNs of the machine, according to the manual of `hostname`.

Here is my PC in local home net.

debian8@hwy:~$ hostname -A
hwy
debian8@hwy:~$ hostname -d
local
debian8@hwy:~$ hostname -f
hwy.local

Why is the output info of `hostname -A` not `hwy.local`?
-A, --all-fqdns Displays,but hwy is not fqdn at all!!

frankbell · 03-03-2017, 09:13 PM

I get this on Slackware --Current.

Code:

$ hostname -A
hostname: invalid option -- 'A'
$ hostname --version
net-tools 1.60
hostname 1.100 (2001-04-14

What distro/version are you using and what version of hostname is installed?

By the way, hostname has been around for a long time. It's highly unlikely that you will get an answer to your "why" question that's other than some variation on "because they wrote it that way." In writing programs, sometimes authors must make arbitrary decisions that make sense to them, but the reasons for the decisions are not readily apparent to others.

ondoho · 03-04-2017, 06:43 AM

Code:

$> hostname -A
hostname: invalid option -- 'A'
Try 'hostname --help' or 'hostname --usage' for more information.
$> hostname --version
hostname (GNU inetutils) 1.9.4
Copyright (C) 2015 Free Software Foundation, Inc.

that's from my archlinux system, but my debian system has the -A option.
it returns an empty string.
which is strange, because 'hostname -fqdn' returns 'localhost'.

luofeiyu · 03-04-2017, 07:32 PM

cat /etc/issue.net
Debian GNU/Linux 8
hostname -V
hostname 3.15

ondoho · 03-07-2017, 02:28 AM

Quote:

Originally Posted by ondoho

Code:

$> hostname -A
hostname: invalid option -- 'A'
Try 'hostname --help' or 'hostname --usage' for more information.
$> hostname --version
hostname (GNU inetutils) 1.9.4
Copyright (C) 2015 Free Software Foundation, Inc.

that's from my archlinux system, but my debian system has the -A option.
it returns an empty string.
which is strange, because 'hostname -fqdn' returns 'localhost'.

i forgot to mention what -A is supposed to do:

Code:

       -A, --all-fqdns
              Displays all FQDNs of the machine. This option enumerates all  configured
              network  addresses  on  all configured network interfaces, and translates
              them to DNS domain names.  Addresses  that  cannot  be  translated  (i.e.
              because  they  do  not have an appropriate reverse IP entry) are skipped.
              Note that different addresses may resolve to the same name, therefore the
              output  may  contain duplicate entries. Do not make any assumptions about
              the order of the output.