$CommandLine (Built-in Mathematica Symbol)

$CommandLine is a list of strings giving the elements of the original operating system command line with which Mathematica was invoked.

$CompilationTarget (Built-in Mathematica Symbol)

$CompilationTarget gives the default value for the option CompilationTarget of Compile.

$ConfiguredKernels (Built-in Mathematica Symbol)

$ConfiguredKernels is the default list of kernels that are configured to be launched for parallel computing.

$Context (Built-in Mathematica Symbol)

$Context is a global variable that gives the current context.

$ContextPath (Built-in Mathematica Symbol)

$ContextPath is a global variable that gives a list of contexts, after $Context, to search in trying to find a symbol that has been entered.

$ControlActiveSetting (Built-in Mathematica Symbol)

$ControlActiveSetting is a symbol whose value is True if it is evaluated while a control is active, or in certain other previewing situations.

$CreationDate (Built-in Mathematica Symbol)

$CreationDate gives the date and time at which the particular release of the Mathematica kernel you are running was created.

$CurrentLink (Built-in Mathematica Symbol)

$CurrentLink is the LinkObject representing the MathLink connection for an external program currently being installed or being called.

$DateStringFormat (Built-in Mathematica Symbol)

$DateStringFormat gives the default format to use for date strings generated by DateString.

$DefaultImagingDevice (Built-in Mathematica Symbol)

$DefaultImagingDevice gives the name of the default imaging device attached to the computer.