The following general rules apply to all commands in CFG, USR, UJP, IIF, FS, GCT, MBX and MCF files:

Name:All command names start with a dollar sign ($).
Case: Case is not significant in command or keyword names.
Length:The maximum length of a command line is 8192 characters.
Layout: Commands may be indented with spaces or tabs to improve readability. Blank lines are ignored.
Format: Command arguments must be separated with one or more spaces or tabs.
Spaces: Command arguments which contain embedded spaces must be surrounded by double quotes. When a double-quote character is needed in such a quoted string, it should be written as two double-quotes (""). Command arguments which do not typically contain embedded blanks should not be surrounded by double-quote characters.
Quotes: A double-quote character (") needed in a quoted command argument should be entered as two double-quotes (""). They may also be entered as @" on a normal command and `" on a command starting with $email...  The repeated double-quote syntax is preferred, however.
Escape: An at-sign (@) is used to introduce a variable name. An at-sign needed in a command argument may be entered as: @@. For more details, see Expansion of Variables. The default escape for $email.. and $sms... commands is a grave accent character (`) instead of @. See also $macro_char.
Comments: A semi-colon (;) or /* sequence, immediately preceded by white space if not at the start of a line, introduces a comment and the remainder of the line is not processed, unless the comment character(s) appear inside a pair of double quotes, in which case they have no special significance.
Date/Time:The USA format (MM/DD/YYYY HH:MM:SS) is always used for date and time parameters on commands.

Note that the treatment of double-quote characters and embedded spaces is special (and does not follow the above rules) on the $email_address, $email_alt_address, $email_from and $email_esender commands. For details, see the command descriptions.