Scripts Essay Research Paper 30

Scripts Essay, Research Paper 3.0 Variables Scripts may contain variables. Variable names must begin with a letter or an underscore (’_'), and may contain any sequence of upper- or lower-case letters, digits, and underscores. You cannot use a reserved word as a variable name. For more information, see the list of reserved words at the end of this document.

Scripts Essay, Research Paper

3.0 Variables

Scripts may contain variables. Variable names must begin with a letter or an underscore (’_'), and may contain any sequence of upper- or lower-case letters, digits, and underscores. You cannot use a reserved word as a variable name. For more information, see the list of reserved words at the end of this document.

You must declare variables before you use them. When you declare a variable, you must also define its type. A variable of a certain type may only contain values of that same type. The following three types of variables are supported:

Type Description

integer A negative or positive number, such as 7, -12, or 5698.

string A series of characters enclosed in double-quotes; for example, “Hello world!” or “Enter password:”.

boolean A logical boolean value of TRUE or FALSE.

Variables are assigned values using the following assignment statement:

variable = expression

The variable gets the evaluated expression.

Examples:

integer count = 5

integer timeout = (4 * 3)

integer i

boolean bDone = FALSE

string szIP = (getip 2)

set ipaddr szIP

3.1 System Variables

System variables are set by scripting commands or are determined by the information your enter when you set up a Dial-Up Networking connection. System variables are read-only, which means they cannot be changed within the script. The system variables are:

Name Type Description

$USERID String The user identification for the current connection. This variable is

the value of the user name specified in the Dial-Up Networking

Connect To dialog box.

$PASSWORD String The password for the current connection. This variable is the

value of the user name specified in the Dial-Up Networking

Connect To dialog box.

$SUCCESS Boolean This variable is set by certain commands to indicate whether or not the command succeeded. A script can make

decisions based upon the value of this variable.

$FAILURE Boolean This variable is set by certain commands to indicate

whether or not the command failed. A script can make decisions

based upon the value of this variable.

These variables may be used wherever an expression of a similar type is used. For example,

transmit $USERID

is a valid command because $USERID is a variable of type string.

4.0 String Literals

Scripting for Dial-Up Networking supports escape sequences and caret translations, as described below.

String Literal Description

^char Caret translation

If char is a value between ‘@’ and ‘_’, the character sequence is translated into a single-byte value between 0 and 31. For example, ^M is converted to a carriage return.

If char is a value between a and z, the character sequence is translated into a single-byte value between 1 and 26.

If char is any other value, the character sequence is not specially treated.

Carriage return

Linefeed

\” Double-quote

\^ Single caret

\< Single ' = Relational Integers

== != Equality Integers, strings, booleans

and Logical AND Booleans

or Logical OR Booleans

Examples:

count = 3 + 5 * 40

transmit “Hello” + ” there”

delay 24 / (7 – 1)

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