SelectedNotebook[] gives the currently selected notebook in the front end.

SyntaxForm is an option for InterpretationBox and TagBox objects that specifies the precedence level to use when the InterpretationBox or TagBox is considered as an operator.

Update[symbol] tells Mathematica that hidden changes have been made which could affect values associated with a symbol. Update[] specifies that the value of any symbol could ...

ColorConvert[expr, colspace] converts color specifications in expr to refer to the color space represented by colspace.

Deployed is an option for displayed objects, cells, and notebooks that specifies whether their contents should be considered deployed, so that elements such as Slider, ...

LanguageCategory is an option for Cell that determines in what category of language the contents of the cell should be assumed to be for purposes of spell checking and ...

ShowStringCharacters is an option for Cell that specifies whether to display " when a string is entered.

Forms of Input and Output How Input and Output Work The Representation of Textual Forms

ReadList["file"] reads all the remaining expressions in a file and returns a list of them. ReadList["file", type] reads objects of the specified type from a file, until the ...

Finding elements that match a pattern. This gives the elements of the list which match the pattern x^_. Here is the total number of elements which match the pattern.