What generates the In/Out CellLabels and how do I change them?

*To*: mathgroup at smc.vnet.net*Subject*: [mg113155] What generates the In/Out CellLabels and how do I change them?*From*: Simon <simonjtyler at gmail.com>*Date*: Fri, 15 Oct 2010 13:53:07 -0400 (EDT)

When Mathematica evaluates a cell, it gives the Input cell and Output cell the CellLabels In[$Line]:= and Out[$Line]= where $Line is a counter that gets incremented on each evaluated input. If you input something like TraditionalForm[expr] or TeXForm[expr] (or any other *Form from $OutputForms) then the name of the form also gets added to the Output cell's label. eg Out[1]//TraditionalForm=. I can't find any way of customising these labels. * They can be disabled in the Preferences dialog. * They don't seem to be in the StyleSheet options for Input and Output cells - although the options pertaining to the CellLabel behaviour are there. * Nor in the Notebook options - although Notebook Options > Evaluation Options > EvaluationCompletionAction can modify the CellLabels. * Nor any of the init.m type configuration files. So, does anyone know where these CellLabels are generated? (Note: This question was also asked at http://stackoverflow.com/q/3938827/421225 I have a feeling that this has been discussed here before - but I could not find the thread)