# Input Syntax Rules

 This section describes the syntax rules that govern an Abaqus input file. All data definitions in Abaqus are accomplished with option blocks—sets of data describing a part of the problem definition. You choose those options that are relevant for a particular application. Options are defined by lines in the input file. Three types of input lines are used in an Abaqus input file: keyword lines, data lines, and comment lines. Only 7-bit ASCII characters are supported in keyword lines and data lines, and a carriage return is required at the end of each line in an input file. Keyword lines introduce options and often have parameters, which appear as words or phrases separated by commas on the keyword line. Parameters are used to define the behavior of an option. Parameters can stand alone or have a value, and they may be required or optional. Data lines, which are used to provide numeric or alphanumeric entries, follow most keyword lines. Any line that begins with stars in columns 1 and 2 (**) is a comment line. Such lines can be placed anywhere in the file. They are ignored by Abaqus, so they will be printed only in the initial listing of the file. There is no restriction on how many or where such lines occur in the file. Relevant parameters and data lines (including the number of entries per data line) are described in the sections of the Abaqus Keywords Guide describing each option. This section describes the general rules that apply to all keyword and data lines. The following topics are discussed:
 Related Topics Abaqus Model Definition

ProductsAbaqus/StandardAbaqus/Explicit