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The Erlang system is started with the following command:
erl <script-flags> <user-flags>
The executable script erl is a front-end to the
Erlang runtime system. The flags
for this program are described below.
Windows 95/NT users will probably want to use the werl program
instead, which uses its own window and supports command-line editing
and has scrollbars.
The erl program on Windows provides no line editing in its
shell and on Windows 95, there is no scroll back to see text which has
scrolled off the screen.
The erl program must be used, however, in pipelines or if you want
to redirect standard input or output.
erl <script-flags> <user-flags>
Starts the Erlang system. The erl script pre-processes some
of the <script-flags> and passes the
flags to the init process in the Erlang system. The
<script-flags> argument is used to initialize the Erlang
kernel processes.
The <user-flags> argument is also passed to the init process
and can be accessed through the init module in the
running system. See init(3).
The following script flags are supported:
Key configuration parameter of the
AppName application. See application(3).
File.boot,
which is used to start the system. See init(3). Unless
File contains an absolute path, the system searches for File.boot in the current and <ERL_INSTALL_DIR>/bin directories .
<ERL_INSTALL_DIR>/bin/start.boot boot script is used.
<ERL_INSTALL_DIR>/lib directory. $Var is expanded
to Directory in the boot script.
mod1.erl mod2.erl .... and
then terminate (with non-zero exit code if the compilation of some
file didn't succeed). Implies -noinput.
Config.config configuration file in order to
configure the system. See application(3).
$HOME/.erlang.cookie file when started and
to set the node cookie to the contents of the user's cookie file. If no such
file is found, the system will create one and it will be filled with a
random string. See -setcookie.
Variable to the value Value
of the Erlang system. For example:
% erl -env DISPLAY gin:0
In this example, an Erlang system is started with the DISPLAY environment
variable set to the value gin:0.
-loader inet
flag is present. On each host, there must be one Erlang node running,
on which the boot_server must be started.
Id must be identical to the name
supplied together with the -sname or -name distribution
flags.
instrument. Functionally, it behaves exactly like
an ordinary Erlang system.
Loader can be efile (use the
local file system), or inet (load using the
boot_server on another Erlang node). If Loader is
something else, the user supplied Loader port program is
started.
-loader flag is omitted efile is assumed.
make:all() in the
current work directory and then terminate. See make(3).
Implies -noinput.
Module.
Mode can be either
interactive to allow automatic code loading, or
embedded to load all code during start-up. See code(3).
Name@Host, where
Host is the fully qualified host name of the current host.
This option also ensures that epmd runs on
the current host before Erlang is started.
See epmd(1).
-noshell.
code server.
See code(3).
Directories to the head of the search
path of the code server, as if code:add_pathsa/1 was
called. See code(3).
Directories to the end of the search
path of the code server, as if code:add_pathsa/1 was
called. See code(3).
-s flag to the init:boot() routine.
See init(3).
Cookie.
As erlang:set_cookie(node(),Cookie) is used, all
other nodes will also be assumed to have their cookies
set to Cookie. In this way, several nodes can
share one magic cookie. Erlang magic cookies are explained
in auth(3).
-name flag, with the exception that
the host name portion of the node name will not be fully qualified.
The following command is used do start Erlang at the host with the name gin.eua.ericsson.se
% erl -sname klacke
Eshell V4.7 (abort with ^G)
(klacke@gin)1>
Only the host name portion of the node name will be relevant. This is
sometimes the only way to run distributed Erlang if the DNS (Domain
Name System) is not running. There can be no communication between
systems running with the -sname flag and those running with
the -name flag, as node names must be unique in distributed
Erlang systems.
xerl.
All these flags are processed during the start-up of the Erlang
kernel servers and before any user processes are started.
All flags are passed to init:boot(Args). See init(3).
All additional flags (<user_flags>) passed to the script will
be passed to init:boot as well, and they can be accessed using
the init module.
The erl script invokes the code for the Erlang virtual
machine. This program supports the following flags:
size.
Number must be
greater than 15 and less than 32769.
size.
The erl script must be changed to set or change these flags.
They can also be set directly with the special flag +. For example:
% erl -name foo +B +l
In this example, a distributed node is started with the break handler turned off and a lot of info is displayed while the code is loading.
The special flag -- is used to end the system flags.
The following example is typical for starting a system:
jam47 -- -s mod1 -s mod2 ........
 |
It is not recommendable to run the code for the
Erlang virtual machine directly, or set any of the flags for it
with the special |
init(3), erl_prim_loader(3), erl_boot_server(3), code(3), application(3), heart(3), net_kernel(3), auth(3), make(3), epmd(1)