Which[test_1, value_1, test_2, value_2, ...] evaluates each of the test_i in turn, returning the value of the value_i corresponding to the first one that yields True.

FindFile[name] finds the file with the specified name that would be loaded by Get[name] and related functions.

Switch[expr, form_1, value_1, form_2, value_2, ...] evaluates expr, then compares it with each of the form_i in turn, evaluating and returning the value_i corresponding to ...

Information[symbol] prints information about a symbol.

Mathematica provides various ways to set up conditionals, which specify that particular expressions should be evaluated only if certain conditions hold. Conditional ...

Goto[tag] scans for Label[tag], and transfers control to that point.

DefaultNewCellStyle is a notebook option which specifies the default style to use for new cells created in the notebook.

NotebookBrowseDirectory is a global option that determines the current working directory.

patt /; test is a pattern which matches only if the evaluation of test yields True. lhs :> rhs /; test represents a rule which applies only if the evaluation of test yields ...

p?test is a pattern object that stands for any expression which matches p, and on which the application of test gives True.