root@hanyw1618-9999:~# hostname
hanyw1618-9999
root@hanyw1618-9999:~# uname -a
Linux hanyw1618-9999 5.15.0-33-generic #34-Ubuntu SMP Wed May 18 13:34:26 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
root@hanyw1618-9999:~# cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 hanyw hanyw666
127.0.0.1 hanyw-ubuntu ubuntu.demo01.hanyw.com bj.ubuntu01.hanyw.com test01.hanyw.com
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
root@hanyw1618-9999:~# uname -n
hanyw1618-9999
2、hostname的man帮助手册如下。
HOSTNAME(1) Linux Programmer's Manual HOSTNAME(1)
NAME
hostname - show or set the system's host name
domainname - show or set the system's NIS/YP domain name
ypdomainname - show or set the system's NIS/YP domain name
nisdomainname - show or set the system's NIS/YP domain name
dnsdomainname - show the system's DNS domain name
SYNOPSIS
hostname [-a|--alias] [-d|--domain] [-f|--fqdn|--long] [-A|--all-fqdns] [-i|--ip-address] [-I|--all-ip-ad‐
dresses] [-s|--short] [-y|--yp|--nis]
hostname [-b|--boot] [-F|--file filename] [hostname]
hostname [-h|--help] [-V|--version]
domainname [nisdomain] [-F file]
ypdomainname [nisdomain] [-F file]
nisdomainname [nisdomain] [-F file]
dnsdomainname
DESCRIPTION
Hostname is used to display the system's DNS name, and to display or set its hostname or NIS domain name.
GET NAME
When called without any arguments, the program displays the current names:
hostname will print the name of the system as returned by the gethostname(2) function.
domainname will print the NIS domainname of the system. domainname uses the gethostname(2) function, while yp‐
domainname and nisdomainname use the getdomainname(2).
dnsdomainname will print the domain part of the FQDN (Fully Qualified Domain Name). The complete FQDN of the
system is returned with hostname --fqdn (but see the warnings in section THE FQDN below).
SET NAME
When called with one argument or with the --file option, the commands set the host name or the NIS/YP domain
name. hostname uses the sethostname(2) function, while all of the three domainname, ypdomainname and nisdo‐
mainname use setdomainname(2). Note, that this is effective only until the next reboot. Edit /etc/hostname
for permanent change.
Note, that only the super-user can change the names.
It is not possible to set the FQDN or the DNS domain name with the dnsdomainname command (see THE FQDN below).
The host name is usually set once at system startup in /etc/init.d/hostname.sh (normally by reading the con‐
tents of a file which contains the host name, e.g. /etc/hostname).
THE FQDN
The FQDN (Fully Qualified Domain Name) of the system is the name that the resolver(3) returns for the host
name, such as, ursula.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 us‐
ing /etc/hosts, DNS, or NIS. For example, if the hostname was "ursula", one might have a line in /etc/hosts
which reads
127.0.1.1 ursula.example.com ursula
Technically: The FQDN is the name getaddrinfo(3) returns for the host name returned by gethostname(2). 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.
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 all FQDNs of the machine. This option enumerates all configured network addresses on all con‐
figured 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 ad‐
dresses 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-existent 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 will show the NIS domain name and not the DNS domain name. Use dnsdomainname instead. See the warn‐
ings in section THE FQDN above, and avoid using this option.
-f, --fqdn, --long
Display the FQDN (Fully Qualified Domain Name). A FQDN consists of a short host name and the DNS domain
name. Unless you are using bind 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 section THE FQDN above und use
hostname --all-fqdns instead wherever possible.
-F, --file filename
Read the host name from the specified file. Comments (lines starting with a `#') are ignored.
-i, --ip-address
Display the network address(es) of the host name. Note that this works only if the host name can be re‐
solved. Avoid using this option; 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 net‐
work 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 host name. This is the host name cut at the first dot.
-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 can also set a new NIS
domain.
-h, --help
Print a usage message and exit.
NOTES
The address families hostname tries when looking up the FQDN, aliases and network addresses of the host are de‐
termined by the configuration of your resolver. For instance, on GNU Libc systems, the resolver can be in‐
structed to try IPv6 lookups first by using the inet6 option in /etc/resolv.conf.
FILES
/etc/hostname Historically this file was supposed to only contain the hostname and not the full canonical FQDN.
Nowadays most software is able to cope with a full FQDN here. This file is read at boot time by the system ini‐
tialization scripts to set the hostname.
/etc/hosts Usually, this is where one sets the domain name by aliasing the host name to the FQDN.
AUTHORS
Peter Tobias,
Bernd Eckenfels, (NIS and manpage).
Michael Meskes,
net-tools 2009-09-16 HOSTNAME(1)
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