Hostname linux what is

Linux hostname command

On Unix-like operating systems, the hostname command shows or sets the system hostname.

This page covers the GNU/Linux version of hostname.

Description

hostname is used to display the system’s DNS name, and to display or set its hostname or NIS (Network Information Services) domain name.

When called without any arguments, hostname displays the name of the system as returned by the gethostname function.

When called with one argument or with the —file option, hostname sets the system’s hostname using the sethostname function. Only the superuser can set the hostname.

The hostname is usually set once at system startup in the script /etc/init.d/hostname.sh normally by reading the contents of a file which contains the hostname, e.g., /etc/hostname.

Syntax

Options

-a, —alias	Display the alias name of the host (if used). This option is deprecated and should not be used anymore.
-A, —all-fqdns	Displays every FQDN 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 DNS 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.
-b, —boot	Always set a hostname; this allows the file specified by -F to be non-existant or empty, in which case the default hostname localhost will be used if none is yet set.
-d, —domain	Display the name of the DNS domain. Don’t use the command domainname to get the DNS domain name because it shows the NIS domain name and not the DNS domain name. Use dnsdomainname instead. See the warnings in the FQDN section, and avoid using this option if at all possible.
-f, —fqdn, —long	Display the FQDN (fully qualified domain name). A FQDN consists of a short hostname and the DNS domain name. Unless you are using BIND (Berkeley Internet Name Domain) or NIS for host lookups, you can change the FQDN and the DNS domain name (which is part of the FQDN) in the /etc/hosts file. See the warnings in the FQDN section, and avoid using this option if at all possible; use hostname —all-fqdns instead.
-F, —file file name	Read the hostname from the specified file. Comments (lines starting with a `#‘) are ignored.
-i, —ip-address	Display the network address(es) of the hostname. Note that this works only if the hostname can be resolved. Avoid using this option if at all possible; use hostname —all-ip-addresses instead.
-I, —all-ip-addresses	Display all network addresses of the host. This option enumerates all configured addresses on all network interfaces. The loopback interface and IPv6 link-local addresses are omitted. Contrary to option -i, this option does not depend on name resolution. Do not make any assumptions about the order of the output.
-s, —short	Display the short hostname. This is the hostname cut at the first dot.
-v, —verbose	Be verbose with all output.
-V, —version	Print version information on standard output and exit successfully.
-y, —yp, —nis	Display the NIS domain name. If a parameter is given (or —file name ) then root (the superuser) can also set a new NIS domain.
-h, —help	Print a help message and exit.

The FQDN

The FQDN (fully qualified domain name) of the system is the name that the resolver returns for the hostname, such as mysubdomain.example.com. It is usually the hostname followed by the DNS domain name (the part after the first dot). You can check the FQDN using hostname —fqdn or the domain name using dnsdomainname.

You cannot change the FQDN with hostname or dnsdomainname.

The recommended method of setting the FQDN is to make the hostname be an alias for the fully qualified name using /etc/hosts, DNS, or NIS. For example, if the hostname was «mysubdomain«, one might have a line in /etc/hosts which reads:

Technically: The FQDN is the name getaddrinfo returns for the hostname returned by gethostname. The DNS domain name is the part after the first dot.

Therefore it depends on the configuration of the resolver (usually in /etc/host.conf) how you can change it. Usually, the hosts file is parsed before DNS or NIS, so it is most common to change the FQDN in /etc/hosts.

If a machine has multiple network interfaces/addresses or is used in a mobile environment, then it may either have multiple FQDNs/domain names or none at all. Therefore avoid using hostname —fqdn, hostname —domain and dnsdomainname.

hostname —ip-address is subject to the same limitations so it should be avoided as well.

Files

/etc/hostname	Historically this file was supposed to only contain the hostname and not the full canonical FQDN. Nowadays most software can cope with a full FQDN here. This file is read at boot time by the system initialization scripts to set the hostname.
/etc/hosts	Usually, this is where one sets the domain name by aliasing the hostname to the FQDN.

Examples

Displays the system hostname.

Related commands

hostid — Print the numeric identifier for the current host.
uname — Print information about the current system.

Источник

Linux Find Out My Machine Name/Hostname

The procedure to find the computer name on Linux:

1. Open a command-line terminal app (select Applications > Accessories > Terminal), and then type:
2. hostname
   OR
   hostnamectl
   OR
   cat /proc/sys/kernel/hostname
3. Press [Enter] key

Linux find hostname using hostnamectl

Type the following command if you are using systemd based Linux distro:
$ hostnamectl

It is possible to filter output using the grep command:
$ hostnamectl | grep ‘hostname’
OR simply use the cat command as follows too:
$ cat /proc/sys/kernel/hostname

Linux find computer name using hostname command

At the terminal type hostname command:
$ hostname
Sample outputs
vivek-laptop.nixcraft.in
Where,

• vivek-laptop : You computer name.
• nixcraft.in : Your dNS domain name.
• vivek-laptop.nixcraft.in : Your computer name with Fully Qualified Domain Name (FQDN).

To see the domain part of the FQDN (Fully Qualified Domain Name), enter:
$ dnsdomainname
Sample outputs:

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How Do I Change My Hostname?

The hostname commands set the host name using the following syntax. Please note that only the super-user / root can change the names. To switch to the root user by typing su – and entering the root password, when prompted.
# hostname newhostname.nixcraft.in
# hostname laptop.nixcraft.net.in
# hostnamectl set-hostname laptop.nixcraft.in
You need to edit /etc/hostname or /etc/sysconfig/network file to set hostname permanently. See our previous FAQ about changing hostname using configuration files.

Conclusion

The hostnamectl command may be used to query and change the system hostname and related settings on modern Linux distros such as Debian, Ubuntu, CentOS/RHEL, Fedora, Arch Linux and more.

Getting help

I strongly suggest that your read the man pages by typing the man command:
$ man hostname
$ man hostnamectl
$ hostnamectl —help

Источник

What is Hostname in Linux and How Can You Change It?

When you visit a website, you type that website’s URL into your browser. That URL is made up of regular words that you can easily understand, like “maketecheasier.com.” Behind the scenes, a DNS server associates that name with a server’s IP address. This system exists because remembering IP addresses is awful, and no one would do it. Hostnames work the same way, only on a local network.

When you give your computer a hostname, it’s a regular word that you understand and can easily type in to identify that computer on your network. Just like a URL, you can substitute that hostname where you would regularly use an IP address. That includes browsing local web pages and using SSH. Unless you’re using a local DNS server, it takes a bit of setting up to make it run smoothly.

See Your Hostname

Viewing your hostname is very easy. Open a terminal and run the hostname command. It’ll display your computer’s current hostname in the terminal window.

Setting Your Hostname

You probably set your computer’s hostname when you installed the operating system, but you can change it any time you choose. Historically, there have been several different ways to set a Linux computer’s hostname, but systemd has greatly simplified the process.

Systemd

On a computer running systemd, you can run the following command to change your computer’s hostname:

Systemd will take care of resetting everything for you.

Old School Method

The most universal traditional method involves modifying two files and restarting your computer. The first file is the “hostname” file. Surprising, right? It’s a plain test file with a single word in it. The system reads that word and sets it as the hostname, so put whatever you like there to make it the system’s hostname. It’s located at “/etc/hostname.”

Next, there’s the “hosts” file. That file tells your system which hostnames to associate with IP addresses. You need to tell it to associate your hostname with the local computer. This one is located at “/etc/hosts;” open it once locate it.

There are two lines there that you need to concern yourself with, and it should look something like this:

Change only the second one that has your current hostname. When you’re done, save, exit, and reboot your computer.

Hosts File

The “hosts” file acts sort of like an ultra-simplified DNS server. It’s the file that lets your computer match up a hostname with an IP address on your network. You can find the file at “/etc/hosts.” Open it once you locate it.

The file is divided into two sections. The top handles the IPv4 addresses that you’re used to, and the bottom is IPv6. If you followed the traditional method, you set your own hostname at the top.

To add the hostnames of other devices on your network, create new lines below the two for your computer, and follow the same format. First, include the local IP of the device. Then, specify its hostname.

When you’re done, restart networking on your computer. It should be as simple as restarting the network service.

Now you’re able to access your new entry via its hostname. Try getting in with SSH.

If you were able to connect, everything is set up and working properly. You now have a solid handle on what hostnames are in Linux and how to make use of them to simplify access to your networked devices.

Nick is a freelance tech. journalist, Linux enthusiast, and a long time PC gamer.

Источник

hostname command in Linux with examples

hostname command in Linux is used to obtain the DNS(Domain Name System) name and set the system’s hostname or NIS(Network Information System) domain name. A hostname is a name which is given to a computer and it attached to the network. Its main purpose is to uniquely identify over a network.

Syntax :

Example: We obtain the system hostname by just typing hostname without any attributes.

Options:

Syntax:

Example:

-A : This option is used to get all FQDNs(Fully Qualified Domain Name) of the host system. It enumerates all configured addresses on all network interfaces. An output may display same entries repetitively.

Syntax :

Example:

-b : Used to always set a hostname. Default name is used if none specified.

Syntax :

Example:

-d : This option is used to get the Domain if local domains are set. It will not return anything(not even a blank line) if no local domain is set.

Syntax :

Example :

-f : This option is used to get the Fully Qualified Domain Name(FQDN). It contains short hostname and DNS domain name.

Syntax:

Example:

-F : This option is used to set the hostname specified in a file. Can be performed by the superuser(root) only.

Syntax:

Example:

-i option:This option is used to get the IP(network) addresses. This option works only if the hostname is resolvable.

Syntax:

Example:

-I : This option is used to get all IP(network) addresses. The option doesn’t depend on resolvability of hostname.

Example:

-s : This option is used to get the hostname in short. The short hostname is the section of hostname before the first period/dot(.). If the hostname has no period, the full hostname is displayed.

Syntax :

Example:

-V : Gives version number as output.

Syntax:

Example:

Note: To set the hostname we can use the command given below:

Here, NEW_HOSTNAME is the new hostname the user wants to give.

Источник