Help: mysh quick commands summary:

In mysh, some commands are identified by a single character, making them easy and quick to enter. Since these commands are always a single character long, it is not necessary (but still acceptable) to place a space between the command and any parameter.

To be processed as quick, the character must be first in the line.

The supported quick commands are:

Quick Long Command Form Form Description

======= ===========
!   history  Display the mysh command history, or if an index is specified,
             retrieve the command with that index value.

#            A comment.

%            Execute a command and then report the elapsed time.

=            All command lines that begin with = are evaluated as Ruby
             expressions. The results of this evaluation are displayed.

?   help     Display help information for mysh with an optional topic.

@   show     The show (or @) command is used to inspect various aspects of
             the mysh environment specified by the item parameter.