1996 2016 Ericsson AB, All Rights Reserved Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. The Initial Developer of the Original Code is Ericsson AB. shell_default Joe Armstrong Joe Armstrong Bjarne Däcker Joe Armstrong 1996-09-09 A shell_default.sgml
shell_default Customizing the Erlang Environment

The functions in shell_default are called when no module name is given in a shell command.

Consider the following shell dialogue:

1 > lists:reverse("abc").
"cba"
2 > c(foo).
{ok, foo}

In command one, the module lists is called. In command two, no module name is specified. The shell searches the modules user_default followed by shell_default for the function foo/1.

shell_default is intended for "system wide" customizations to the shell. user_default is intended for "local" or individual user customizations.
Hint

To add your own commands to the shell, create a module called user_default and add the commands you want. Then add the following line as the first line in your .erlang file in your home directory. 

code:load_abs("$PATH/user_default").

$PATH is the directory where your user_default module can be found.