Network Security Tools

Strings

A string is a collection of characters. abcdefg, Hello World, and Boeing 747 are all examples of strings. Consider the following NASL script:

mystring="Hello. I am a string!\n";
display(mystring);

The \n at the end of mystring is an escape character and is equivalent to a newline character. Table 1-1 lists common escape characters applicable to NASL.

Table 1-1. Escape characters

Escape character	Description
\'	Single quote.
\"	Double quote.
\\	Backslash.
\r	Line feed.
\n	Newline.
\t	Horizontal tab.
\x(integer)	ASCII equivalent. For example, \x7A will be converted to z.
\v	Vertical tab.

Note that a string inside double quotes (“) is left as is. Therefore, if you define a string using double quotes, escape sequences will not be translated. Also note that the display( ) function calls the string( ) function before displaying data on the console, and it is the string( ) function that converts the escape sequences. That is why our escape sequences are translated in the preceding examples even though we define them using double quotes.