Introduction

Variables are integral data storage objects in the Universal Scripting Engine.

Variable Types

There are two types of variables:

• Script
• Global (user-defined and built-in)

Variable Names

There are no restrictions on variable names except:

• They cannot contain double-quote marks ( " ) or spaces.
• UDM reserves variable names beginning with an underscore ( _ ) for its own internal (built-in) variables (see UDM - Built-In Variables). You cannot create a script variable or user-defined global variable that begins with an underscore ( _ ).

Variable Reference

To obtain the value of a variable, you must create a reference for that variable. The reference can appear anywhere in a script line. It is replaced with the value of the referenced variable.

Referencing the value of a global variable in a script is done exactly the same way as for a script variable:

$(variable_name)

For example:

set srcfile=myfile.txt
set dstfile=yourfile.txt
copy src=$(srcfile) dst=$(dstfile)

Variable Attributes

In addition to accessing the value of a variable, you can access information about that variable through its attributes.

variable attribute is referenced by putting a dot ( . ) after the variable name in a variable reference. For example:

$(name.attribute)

There are two variable attributes that can be used for any variable:

• exists
• length

exists Attribute

The exists attribute expands to yes if a variable with that name exists at any scope; it expands to no if no variable with that name exists.

length Attribute

The length attribute expands to the length of the variable's value. If the length attribute is used for a variable that does not exist, an error is issued.