.TH net_adm 3erl "kernel 5.1.1" "Ericsson AB" "Erlang Module Definition"
.SH NAME
net_adm \- Various Erlang net administration routines.
.SH DESCRIPTION
.LP
This module contains various network utility functions\&.
.SH EXPORTS
.LP
.nf

.B
dns_hostname(Host) -> {ok, Name} | {error, Host}
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Host = atom() | string()
.br
Name = string()
.br
.RE
.RE
.RS
.LP
Returns the official name of \fIHost\fR\&, or \fI{error, Host}\fR\& if no such name is found\&. See also \fB\fIinet(3erl)\fR\&\fR\&\&.
.RE

.LP
.nf

.B
host_file() -> Hosts | {error, Reason}
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Hosts = [Host :: atom()]
.br
Reason = 
.br
    \fBfile:posix()\fR\& |
.br
    badarg |
.br
    terminated |
.br
    system_limit |
.br
    {Line :: integer(), Mod :: module(), Term :: term()}
.br
.RE
.RE
.RS
.LP
Reads file \fI\&.hosts\&.erlang\fR\&, see section \fBFiles\fR\&\&. Returns the hosts in this file as a list\&. Returns \fI{error, Reason}\fR\& if the file cannot be read or the Erlang terms on the file cannot be interpreted\&.
.RE

.LP
.nf

.B
localhost() -> Name
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Name = string()
.br
.RE
.RE
.RS
.LP
Returns the name of the local host\&. If Erlang was started with command-line flag \fI-name\fR\&, \fIName\fR\& is the fully qualified name\&.
.RE

.LP
.nf

.B
names() -> {ok, [{Name, Port}]} | {error, Reason}
.br
.fi
.br
.nf

.B
names(Host) -> {ok, [{Name, Port}]} | {error, Reason}
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Host = atom() | string() | \fBinet:ip_address()\fR\&
.br
Name = string()
.br
Port = integer() >= 0
.br
Reason = address | \fBfile:posix()\fR\&
.br
.RE
.RE
.RS
.LP
Similar to \fIepmd -names\fR\&, see \fB\fIerts:epmd(1)\fR\&\fR\&\&. \fIHost\fR\& defaults to the local host\&. Returns the names and associated port numbers of the Erlang nodes that \fIepmd\fR\& registered at the specified host\&. Returns \fI{error, address}\fR\& if \fIepmd\fR\& is not operational\&.
.LP
\fIExample:\fR\&
.LP
.nf

(arne@dunn)1> net_adm:names()\&.
{ok,[{"arne",40262}]}
.fi
.RE

.LP
.nf

.B
ping(Node) -> pong | pang
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Node = atom()
.br
.RE
.RE
.RS
.LP
Sets up a connection to \fINode\fR\&\&. Returns \fIpong\fR\& if it is successful, otherwise \fIpang\fR\&\&.
.RE

.LP
.nf

.B
world() -> [node()]
.br
.fi
.br
.nf

.B
world(Arg) -> [node()]
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Arg = \fBverbosity()\fR\&
.br
.nf
\fBverbosity()\fR\& = silent | verbose
.fi
.br
.RE
.RE
.RS
.LP
Calls \fInames(Host)\fR\& for all hosts that are specified in the Erlang host file \fI\&.hosts\&.erlang\fR\&, collects the replies, and then evaluates \fIping(Node)\fR\& on all those nodes\&. Returns the list of all nodes that are successfully pinged\&.
.LP
\fIArg\fR\& defaults to \fIsilent\fR\&\&. If \fIArg == verbose\fR\&, the function writes information about which nodes it is pinging to \fIstdout\fR\&\&.
.LP
This function can be useful when a node is started, and the names of the other network nodes are not initially known\&.
.LP
Returns \fI{error, Reason}\fR\& if \fIhost_file()\fR\& returns \fI{error, Reason}\fR\&\&.
.RE

.LP
.nf

.B
world_list(Hosts) -> [node()]
.br
.fi
.br
.nf

.B
world_list(Hosts, Arg) -> [node()]
.br
.fi
.br
.RS
.LP
Types:

.RS 3
Hosts = [atom()]
.br
Arg = \fBverbosity()\fR\&
.br
.nf
\fBverbosity()\fR\& = silent | verbose
.fi
.br
.RE
.RE
.RS
.LP
Same as \fB\fIworld/0,1\fR\&\fR\&, but the hosts are specified as argument instead of being read from \fI\&.hosts\&.erlang\fR\&\&.
.RE

.SH "FILES"

.LP
File \fI\&.hosts\&.erlang\fR\& consists of a number of host names written as Erlang terms\&. It is looked for in the current work directory, the user\&'s home directory, and \fI$OTP_ROOT\fR\& (the root directory of Erlang/OTP), in that order\&.
.LP
The format of file \fI\&.hosts\&.erlang\fR\& must be one host name per line\&. The host names must be within quotes\&.
.LP
\fIExample:\fR\&
.LP
.nf

\&'super.eua.ericsson.se'.
\&'renat.eua.ericsson.se'.
\&'grouse.eua.ericsson.se'.
\&'gauffin1.eua.ericsson.se'.
^ (new line)
.fi