Syntax Utilities

When creating commands, certain syntactical constructions are available to ease readability, speed command entry, or provide structure.

Command Abbreviation

Commands may be shortened to their first few letters. In this documentation, the underlined characters in a command signature (cf. zone list) indicate the minimum necessary characters to type for correct recognition of the command by the command processor. Please observe that a hyphenated command will require the minimum characters and the hyphen (e.g., zone apply-remove may be shortened to z a-r). Command abbreviation can be helpful when issuing commands in the i Console, but is generally eschewed in data files. The data files accompanying the examples in this documentation never use abbreviations.

Line Continuation

There is no limit to the length of a command; a single command may contain any number of characters in a single line. However, in practice it is desirable to use multiple lines to break up long commands. An ampersand (&) or an ellipsis (...) can be given at the end of an input line to denote that the next line will be a continuation of that line. Both are valid and interchangeable. Note blank spaces are ignored (see “Delimiters” below).

zone create brick size 20 1 20 point 0 (3.0,0.0,0.0) ...
                               point 1 (20.0,0.0,0.0) &
                               point 3 (3.0,0.0,10.0) ...
                               ratio 1.08 1.0 0.97


Many keywords are followed by a value or series of values that provide the input required by the keyword (this could be numeric, boolean, string, vector, or other input, including the name of a FISH function).

For numeric input, the decimal point may be omitted from a required real value, but may not appear in an integer value.

See the topic Command and FISH Highlighting in the Program and Command and FISH Reference Notation in the Documents as well for a guide to the appearance of commands in the program and in this documentation, respectively.


Commands, keywords, and numeric values may be separated by any number of spaces, or by any of the following delimiters:

( ) , =


A semicolon ( ; ) may be used to precede comments; anything that follows a semicolon in an input line is ignored. It is useful, and strongly recommended, to include comments in data files. Not only is the input documented in this way, but the comments are echoed to the output as well, providing the opportunity for quality assurance in model analysis.