Mathematica allows almost every aspect of sessions to be customized, under full programmatic control.
NotebookAutoSave is a notebook option which specifies whether the notebook should automatically be saved after each piece of output generated by evaluation in it.
$Aborted is a special symbol that is returned as the result from a calculation that has been aborted.
PreemptProtect[expr] evaluates expr, without any interruption from preemptive evaluations.
"Interrupting Calculations" describes how you can interrupt a Mathematica computation by pressing appropriate keys on your keyboard. In some cases, you may want to simulate ...
Update
(Built-in Mathematica Symbol) Update[symbol] tells Mathematica that hidden changes have been made which could affect values associated with a symbol. Update[] specifies that the value of any symbol could ...
MatchLocalNames is an option for Trace and related functions that specifies whether symbols such as x should match symbols with local names of the form x$nnn.
AbortProtect[expr] evaluates expr, saving any aborts until the evaluation is complete.
"How to" Topics Building Up Calculations Lists