.TH net_adm 3erl "kernel 3.0.3" "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 \fIinet(3erl)\fR\&\&.
.RE

.LP
.nf

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

.RS 3
Hosts = [Host :: atom()]
.br
Reason = \fBfile:posix()\fR\&
.br
       | badarg
.br
       | terminated
.br
       | system_limit
.br
       | {Line :: integer(), Mod :: module(), Term :: term()}
.br
.RE
.RE
.RS
.LP
Reads the \fI\&.hosts\&.erlang\fR\& file, see the section \fIFiles\fR\& below\&. Returns the hosts in this file as a list, or returns \fI{error, Reason}\fR\& if the file could not be read or the Erlang terms on the file could not 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 the \fI-name\fR\& command line flag, \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 \fIepmd(1)\fR\&\&. \fIHost\fR\& defaults to the local host\&. Returns the names and associated port numbers of the Erlang nodes that \fIepmd\fR\& at the specified host has registered\&.
.LP
Returns \fI{error, address}\fR\& if \fIepmd\fR\& is not running\&.
.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
Tries to set up a connection to \fINode\fR\&\&. Returns \fIpang\fR\& if it fails, or \fIpong\fR\& if it is successful\&.
.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
This function calls \fInames(Host)\fR\& for all hosts which 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 were, successfully pinged\&.
.LP
\fIArg\fR\& defaults to \fIsilent\fR\&\&. If \fIArg == verbose\fR\&, the function writes information about which nodes it is pinging to stdout\&.
.LP
This function can be useful when a node is started, and the names of the other nodes in the network are not initially known\&.
.LP
Failure: \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
As \fIworld/0,1\fR\&, but the hosts are given as argument instead of being read from \fI\&.hosts\&.erlang\fR\&\&.
.RE

.SH "FILES"

.LP
The \fI\&.hosts\&.erlang\fR\& file 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 the \fI\&.hosts\&.erlang\fR\& file must be one host name per line\&. The host names must be within quotes as shown in the following example:
.LP
.nf

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