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)