Provided by: erlang-base-hipe_18.3-dfsg-1ubuntu3.1_amd64 
NAME
erl_call - Call/Start a Distributed Erlang Node
DESCRIPTION
erl_call makes it possible to start and/or communicate with a distributed Erlang node. It is built upon
the erl_interface library as an example application. Its purpose is to use an Unix shell script to
interact with a distributed Erlang node. It performs all communication with the Erlang rex server, using
the standard Erlang RPC facility. It does not require any special software to be run at the Erlang target
node.
The main use is to either start a distributed Erlang node or to make an ordinary function call. However,
it is also possible to pipe an Erlang module to erl_call and have it compiled, or to pipe a sequence of
Erlang expressions to be evaluated (similar to the Erlang shell).
Options, which cause stdin to be read, can be used with advantage as scripts from within (Unix) shell
scripts. Another nice use of erl_call could be from (http) CGI-bin scripts.
EXPORTS
erl_call <options>
Each option flag is described below with its name, type and meaning.
-a [Mod [Fun [Args]]]]:
(optional): Applies the specified function and returns the result. Mod must be specified,
however start and [] are assumed for unspecified Fun and Args, respectively. Args should be in
the same format as for erlang:apply/3. Note that this flag takes exactly one argument, so
quoting may be necessary in order to group Mod, Fun and Args, in a manner dependent on the
behavior of your command shell.
-c Cookie:
(optional): Use this option to specify a certain cookie. If no cookie is specified, the
~/.erlang.cookie file is read and its content are used as cookie. The Erlang node we want to
communicate with must have the same cookie.
-d:
(optional): Debug mode. This causes all IO to be output to the file ~/.erl_call.out.Nodename,
where Nodename is the node name of the Erlang node in question.
-e:
(optional): Reads a sequence of Erlang expressions, separated by ',' and ended with a '.',
from stdin until EOF (Control-D). Evaluates the expressions and returns the result from the
last expression. Returns {ok,Result} if successful.
-h HiddenName:
(optional): Specifies the name of the hidden node that erl_call represents.
-m:
(optional): Reads an Erlang module from stdin and compiles it.
-n Node:
(one of -n, -name, -sname is required): Has the same meaning as -name and can still be used
for backwards compatibility reasons.
-name Node:
(one of -n, -name, -sname is required): Node is the name of the node to be started or
communicated with. It is assumed that Node is started with erl -name, which means that fully
qualified long node names are used. If the -s option is given, an Erlang node will (if
necessary) be started with erl -name.
-q:
(optional): Halts the Erlang node specified with the -n switch. This switch overrides the -s
switch.
-r:
(optional): Generates a random name of the hidden node that erl_call represents.
-s:
(optional): Starts a distributed Erlang node if necessary. This means that in a sequence of
calls, where the '-s' and '-n Node' are constant, only the first call will start the Erlang
node. This makes the rest of the communication very fast. This flag is currently only
available on the Unix platform.
-sname Node:
(one of -n, -name, -sname is required): Node is the name of the node to be started or
communicated with. It is assumed that Node is started with erl -sname which means that short
node names are used. If -s option is given, an Erlang node will be started (if necessary) with
erl -sname.
-v:
(optional): Prints a lot of verbose information. This is only useful for the developer and
maintainer of erl_call.
-x ErlScript:
(optional): Specifies another name of the Erlang start-up script to be used. If not specified,
the standard erl start-up script is used.
EXAMPLES
Starts an Erlang node and calls erlang:time/0.
erl_call -s -a 'erlang time' -n madonna
{18,27,34}
Terminates an Erlang node by calling erlang:halt/0.
erl_call -s -a 'erlang halt' -n madonna
An apply with several arguments.
erl_call -s -a 'lists map [{math,sqrt},[1,4,9,16,25]]' -n madonna
Evaluates a couple of expressions. The input ends with EOF (Control-D).
erl_call -s -e -n madonna
statistics(runtime),
X=1,
Y=2,
{_,T}=statistics(runtime),
{X+Y,T}.
^D
{ok,{3,0}}
Compiles a module and runs it. Again, the input ends with EOF (Control-D). (In the example shown, the
output has been formatted afterwards).
erl_call -s -m -a lolita -n madonna
-module(lolita).
-compile(export_all).
start() ->
P = processes(),
F = fun(X) -> {X,process_info(X,registered_name)} end,
lists:map(F,[],P).
^D
[{<madonna@chivas.du.etx.ericsson.se,0,0>,
{registered_name,init}},
{<madonna@chivas.du.etx.ericsson.se,2,0>,
{registered_name,erl_prim_loader}},
{<madonna@chivas.du.etx.ericsson.se,4,0>,
{registered_name,error_logger}},
{<madonna@chivas.du.etx.ericsson.se,5,0>,
{registered_name,application_controller}},
{<madonna@chivas.du.etx.ericsson.se,6,0>,
{registered_name,kernel}},
{<madonna@chivas.du.etx.ericsson.se,7,0>,
[]},
{<madonna@chivas.du.etx.ericsson.se,8,0>,
{registered_name,kernel_sup}},
{<madonna@chivas.du.etx.ericsson.se,9,0>,
{registered_name,net_sup}},
{<madonna@chivas.du.etx.ericsson.se,10,0>,
{registered_name,net_kernel}},
{<madonna@chivas.du.etx.ericsson.se,11,0>,
[]},
{<madonna@chivas.du.etx.ericsson.se,12,0>,
{registered_name,global_name_server}},
{<madonna@chivas.du.etx.ericsson.se,13,0>,
{registered_name,auth}},
{<madonna@chivas.du.etx.ericsson.se,14,0>,
{registered_name,rex}},
{<madonna@chivas.du.etx.ericsson.se,15,0>,
[]},
{<madonna@chivas.du.etx.ericsson.se,16,0>,
{registered_name,file_server}},
{<madonna@chivas.du.etx.ericsson.se,17,0>,
{registered_name,code_server}},
{<madonna@chivas.du.etx.ericsson.se,20,0>,
{registered_name,user}},
{<madonna@chivas.du.etx.ericsson.se,38,0>,
[]}]