to get the file

Variables
• There are no type declarations because of dynamic typing
• The type of a variable is set every time it is assigned a value
• An unassigned ( unbound ) variable has the value, NULL
• A variable of NULL in the expression will be coerced to a value
dictated by the context of the use
(Ex) If a number, NULL is coerced to 0
If a string, NULL is coerced to the empty string
• The unset function sets a variable to NULL
• The IsSet function tests whether a variable is NULL
(Ex) IsSet ( $fruit ) returns TRUE if $fruit has non-NULL value
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