Command: hostname explained
I have seen a lot of people telling people to use the command hostname to get FQDN but almost none that have explained to junior people what the command actually does more than hostname -f. So I decided to start explaining a lot of the Linux commands that are used daily if not weekly as a Linux System Administrator. So enjoy the first of many commands I will explain in detail here at geekcorner.sitedevelopments.net.
This command can read or set the hostname or the NIS domain name. You can
also read the DNS domain or the FQDN (fully qualified domain name).
Unless you are using bind or NIS for host lookups you can change the
FQDN (Fully Qualified Domain Name) and the DNS domain name (which is
part of the FQDN) in the /etc/hosts file.
Usage:
-i, –ip-address addresses for the hostname
-I, –all-ip-addresses all addresses for the host
Check ip Address for the hostname
hostname i
hostname -i 127.0.0.1
Check all IP Addresses for the hostname
-I, –all-ip-addresses all addresses for the host
hostname -I
As you see below the command do not show the loopback IP address only sharp ip adresses.,
hostname -I 10.101.1.152
Check the aliases for hostname
-a, –alias alias names
hostname -a
$ hostname -a sesstl168 localhost.localdomain localhost
Check the short host name
-s, –short short host name
hostname -s
hostname -s sesstl168
Check the Fully Qualified Domain Name (FQDN)
-f, –fqdn, –long long host name (FQDN)
hostname -f
hostname -f sesstl168.sitedevelopments.local
Check all FDQDN
-A, –all-fqdns all long host names (FQDNs)
hostname -A
hostname -A sesstl168.sitedevelopments.net
As you see here the command hostname -A will only show the FQDN that have a real IP address it will not show loopback FQDN
Set hostname from a file
hostname [-v] {hostname|-F file}Command Explanation:
hostname [-v] display hostname
-F, –file read hostname or NIS domainname from given file
In the example below I load the hostname newhostname from the file myhostname that are located in my home folder.
As you see the file contains only the hostname
cat /home/johan/myhostname newhostname
sudo hostname -v hostname -F /home/johan/mydomainname
[sudo] password for johan: >> newhostname Setting hostname to `newhostname'
To check the result of the command we just typed type: hostname -v it will display the name.
Below is the output of hostname -v after I ran the command above.
$ hostname -v gethostname()=`newhostname' newhostname
| hostname [-v] [-d | -f | -s | -a | -i | -y | -A | -I] display formatted name |
hostname [-v] display hostname
| hostname -V | –version | -h | –help print info and exit |
hostname -Vh
[c-johsor@sesstl168 ~]$ hostname -Vh net-tools 1.60 hostname 1.100 (2001-04-14) [c-johsor@sesstl168 ~]$
Finaly you can use hostname -h to get help
hostname -h
Usage: hostname [-v] {hostname|-F file} set hostname (from file)
domainname [-v] {nisdomain|-F file} set NIS domainname (from file)
hostname [-v] [-d|-f|-s|-a|-i|-y|-A|-I] display formatted name
hostname [-v] display hostname
hostname -V|--version|-h|--help print info and exit
dnsdomainname=hostname -d, {yp,nis,}domainname=hostname -y
-s, --short short host name
-a, --alias alias names
-i, --ip-address addresses for the hostname
-I, --all-ip-addresses all addresses for the host
-f, --fqdn, --long long host name (FQDN)
-A, --all-fqdns all long host names (FQDNs)
-d, --domain DNS domain name
-y, --yp, --nis NIS/YP domainname
-F, --file read hostname or NIS domainname from given file
This command can read or set the hostname or the NIS domainname. You can
also read the DNS domain or the FQDN (fully qualified domain name).
Unless you are using bind or NIS for host lookups you can change the
FQDN (Fully Qualified Domain Name) and the DNS domain name (which is
part of the FQDN) in the /etc/hosts file.That’s all folk.
Do you like to check out other commands that I’m explaining check out the below post:<ul class = "posts-by-tag-list">
</ul>