$Line (Built-in Mathematica Symbol)

$Line is a global variable that specifies the number of the current input line.

$Linked (Built-in Mathematica Symbol)

$Linked is True if the Mathematica kernel is being run through MathLink.

$MachineID (Built-in Mathematica Symbol)

$MachineID is a string that gives, if possible, a unique identification code for the computer on which Mathematica is being run.

$Notebooks (Built-in Mathematica Symbol)

$Notebooks is True if Mathematica is being used with a notebook-based front end.

$OperatingSystem (Built-in Mathematica Symbol)

$OperatingSystem is a string giving the type of operating system under which Mathematica is being run.

$System (Built-in Mathematica Symbol)

$System is a string describing the type of computer system on which Mathematica is being run.

$UserDocumentsDirectory (Built-in Mathematica Symbol)

$UserDocumentsDirectory gives your default "documents" directory.

Algebraic Manipulation (Mathematica Overview)

Structural Operations on Polynomials Finding the Structure of a Polynomial Polynomial Orderings

Editing Mathematica Graphics Overview (Mathematica Overview)

Introduction to Editing Mathematica Graphics Drawing Tools Selecting Graphics Objects

DatabaseLink Connections and Resources (DatabaseLink Guide)

DatabaseLink provides a number of functions for connection to an SQL database. It also supports a resource mechanism that allows the details of how the connection is set up ...