1HOSTNAME(1) Linux Programmer's Manual HOSTNAME(1)
2
6 hostname - show or set the system's host name
7 domainname - show or set the system's NIS/YP domain name
8 ypdomainname - show or set the system's NIS/YP domain name
9 nisdomainname - show or set the system's NIS/YP domain name
10 dnsdomainname - show the system's DNS domain name
11
14 hostname [-a|--alias] [-d|--domain] [-f|--fqdn|--long] [-A|--all-fqdns]
15 [-i|--ip-address] [-I|--all-ip-addresses] [-s|--short] [-y|--yp|--nis]
16 hostname [-b|--boot] [-F|--file filename] [hostname]
17 hostname [-h|--help] [-V|--version]
18 domainname [nisdomain] [-F file]
20 ypdomainname [nisdomain] [-F file]
21 nisdomainname [nisdomain] [-F file]
22 dnsdomainname
24
27 Hostname is used to display the system's DNS name, and to display or
28 set its hostname or NIS domain name.
29 GET NAME
32 When called without any arguments, the program displays the current
33 names:
34 hostname will print the name of the system as returned by the gethost‐
36 name(2) function.
37 domainname will print the NIS domainname of the system. domainname
39 uses the gethostname(2) function, while ypdomainname and nisdomainname
40 use the getdomainname(2).
41 dnsdomainname will print the domain part of the FQDN (Fully Qualified
43 Domain Name). The complete FQDN of the system is returned with hostname
44 --fqdn (but see the warnings in section THE FQDN below).
45 The function gethostname(2) is used to get the hostname. When the
48 hostname -a, -d, -f or -i is called will gethostbyname(3) be called.
49 The difference in gethostname(2) and gethostbyname(3) is that gethost‐
50 byname(3) is network aware, so it consults /etc/nsswitch.conf and
51 /etc/host.conf to decide whether to read information in /etc/hostname
52 or /etc/hosts
53 SET NAME
56 When called with one argument or with the --file option, the commands
57 set the host name or the NIS/YP domain name. hostname uses the
58 sethostname(2) function, while all of the three domainname, ypdomain‐
59 name and nisdomainname use setdomainname(2). Note, that this is effec‐
60 tive only until the next reboot. Edit /etc/hostname for permanent
61 change.
62 Note, that only the super-user can change the names.
64 It is not possible to set the FQDN or the DNS domain name with the dns‐
66 domainname command (see THE FQDN below).
67 The host name is usually set once at system startup (normally by read‐
69 ing the contents of a file which contains the host name, e.g.
70 /etc/hostname).
71 THE FQDN
74 The FQDN (Fully Qualified Domain Name) of the system is the name that
75 the resolver(3) returns for the host name, such as, ursula.example.com.
76 It is usually the hostname followed by the DNS domain name (the part
77 after the first dot). You can check the FQDN using hostname --fqdn or
78 the domain name using dnsdomainname.
79 You cannot change the FQDN with hostname or dnsdomainname.
81 The recommended method of setting the FQDN is to make the hostname be
83 an alias for the fully qualified name using /etc/hosts, DNS, or NIS.
84 For example, if the hostname was "ursula", one might have a line in
85 /etc/hosts which reads
86 127.0.1.1 ursula.example.com ursula
88 Technically: The FQDN is the name getaddrinfo(3) returns for the host
90 name returned by gethostname(2). The DNS domain name is the part after
91 the first dot.
92 Therefore it depends on the configuration of the resolver (usually in
94 /etc/host.conf) how you can change it. Usually the hosts file is parsed
95 before DNS or NIS, so it is most common to change the FQDN in
96 /etc/hosts.
97 If a machine has multiple network interfaces/addresses or is used in a
99 mobile environment, then it may either have multiple FQDNs/domain names
100 or none at all. Therefore avoid using hostname --fqdn, hostname
101 --domain and dnsdomainname. hostname --ip-address is subject to the
102 same limitations so it should be avoided as well.
103
106 -a, --alias
107 Display the alias name of the host (if used). This option is
108 deprecated and should not be used anymore.
109 -A, --all-fqdns
111 Displays all FQDNs of the machine. This option enumerates all
112 configured network addresses on all configured network inter‐
113 faces, and translates them to DNS domain names. Addresses that
114 cannot be translated (i.e. because they do not have an appropri‐
115 ate reverse IP entry) are skipped. Note that different addresses
116 may resolve to the same name, therefore the output may contain
117 duplicate entries. Do not make any assumptions about the order
118 of the output.
119 -b, --boot
121 Always set a hostname; this allows the file specified by -F to
122 be non-existant or empty, in which case the default hostname
123 localhost will be used if none is yet set.
124 -d, --domain
126 Display the name of the DNS domain. Don't use the command
127 domainname to get the DNS domain name because it will show the
128 NIS domain name and not the DNS domain name. Use dnsdomainname
129 instead. See the warnings in section THE FQDN above, and avoid
130 using this option.
131 -f, --fqdn, --long
133 Display the FQDN (Fully Qualified Domain Name). A FQDN consists
134 of a short host name and the DNS domain name. Unless you are
135 using bind or NIS for host lookups you can change the FQDN and
136 the DNS domain name (which is part of the FQDN) in the
137 /etc/hosts file. See the warnings in section THE FQDN above und
138 use hostname --all-fqdns instead wherever possible.
139 -F, --file filename
141 Read the host name from the specified file. Comments (lines
142 starting with a `#') are ignored.
143 -i, --ip-address
145 Display the network address(es) of the host name. Note that this
146 works only if the host name can be resolved. Avoid using this
147 option; use hostname --all-ip-addresses instead.
148 -I, --all-ip-addresses
150 Display all network addresses of the host. This option enumer‐
151 ates all configured addresses on all network interfaces. The
152 loopback interface and IPv6 link-local addresses are omitted.
153 Contrary to option -i, this option does not depend on name reso‐
154 lution. Do not make any assumptions about the order of the out‐
155 put.
156 -s, --short
158 Display the short host name. This is the host name cut at the
159 first dot.
160 -V, --version
162 Print version information on standard output and exit success‐
163 fully.
164 -y, --yp, --nis
166 Display the NIS domain name. If a parameter is given (or --file
167 name ) then root can also set a new NIS domain.
168 -h, --help
170 Print a usage message and exit.
171
173 The address families hostname tries when looking up the FQDN, aliases
174 and network addresses of the host are determined by the configuration
175 of your resolver. For instance, on GNU Libc systems, the resolver can
176 be instructed to try IPv6 lookups first by using the inet6 option in
177 /etc/resolv.conf.
178
180 /etc/hostname Historically this file was supposed to only contain the
181 hostname and not the full canonical FQDN. Nowadays most software is
182 able to cope with a full FQDN here. This file is read at boot time by
183 the system initialization scripts to set the hostname.
184 /etc/hosts Usually, this is where one sets the domain name by aliasing
186 the host name to the FQDN.
187
189 Peter Tobias, <tobias@et-inf.fho-emden.de>
190 Bernd Eckenfels, <net-tools@lina.inka.de> (NIS and manpage).
191 Michael Meskes, <meskes@debian.org>
192net-tools 2009-09-16 HOSTNAME(1)