String

A string is a sequence of characters that is enclosed by double quotes. A string can also contain double quotes, but the quotes must be immediately preceded by a backslash. A backslash is represented in a string as \\. Quotes are not required if a string begins with a letter, and contains only letters, numbers, dashes (-), and underscores (_).

For example, a string that defines a network interface such as eth0 does not require quotes since it contains only letters and numbers. However a string that defines an IP address contains periods and requires quotes- such as: "192.168.100.1".

Integer

Signed integer constants are a sequence of digits from 0 to 9. They may be preceded by a dash, and are interpreted in base 10. Integers cannot exceed the value of a 32-bit signed integer: 21471183247.

Boolean

A boolean is an integer, the possible values of which are 0 (false) and 1 (true).