There are two variants of command syntax, viz: batch mode and interactive mode. Batch mode is the default when reading commands from a file. Interactive mode is the default when commands are typed at a prompt by a user. Certain commands, such as INSERT (see INSERT), may explicitly change the syntax mode.
In batch mode, any line that contains a non-space character in the leftmost column begins a new command. Thus, each command consists of a flush-left line followed by any number of lines indented from the left margin. In this mode, a plus or minus sign (‘+’, ‘−’) as the first character in a line is ignored and causes that line to begin a new command, which allows for visual indentation of a command without that command being considered part of the previous command. The period terminating the end of a command is optional but recommended.
In interactive mode, each command must either be terminated with a period, or an empty line must follow the command. The use of (‘+’ and ‘−’ as continuation characters is not permitted.