({{, (RefLink[$Notebooks, paclet:ref/$Notebooks])
is (RefLink[True, paclet:ref/True]) if the Wolfram System is being used with a notebook-based front end. }})

OpenersNotesSection(Spacer1)Details

(RefLink[$Notebooks, paclet:ref/$Notebooks]) is automatically set by the front end when it starts the Wolfram Language kernel.

OpenersPrimaryExamplesSection(Spacer1)Examples  (2)

OpenersExampleSection0(Spacer1)Basic Examples  (1)

This tells you that the Wolfram System is being used with a notebook-based front end:

$Notebooks

OpenersExampleSection1(Spacer1)Applications  (1)

An application can check (RefLink[$Notebooks, paclet:ref/$Notebooks]) to decide how to behave:

If[$Notebooks,Print["Using notebook interface"], Print["Using text interface"]]

({{DocumentationFooterIconsRelatedFunction.png, ({{See Also}, {(RefLink[$FrontEnd, paclet:ref/$FrontEnd])  ▪  (RefLink[$Linked, paclet:ref/$Linked])  ▪  (RefLink[$BatchInput, paclet:ref/$BatchInput])  ▪  (RefLink[UsingFrontEnd, paclet:ref/UsingFrontEnd])}})}})

({{DocumentationFooterIconsRelatedTutorial.png, ({{Tutorials}, {▪(RefLinkPlain[Global System Information, paclet:tutorial/GlobalSystemInformation])}})}})