[Novalug] a regex puzzle

[daniel]

I see what it does.  Not going to spoil it for anyone who wants to try 
it themselves.  I'd like to know why.

To help myself understand better I altered the line to read:

$ echo NovaLUG | sed 's/L*/,/g'

and then again to:

$ echo NovaLUG | sed 's/LUG*/,/g'

The results are interesting.


On 03/19/2012 12:08 PM, Jon LaBadie wrote:
> The recent discussions of pattern matching and regular
> expressions brought to mind a favorite puzzle.
>
> Sed can be used to modify strings with its substitute
> command, eg s/existing stuff/new stuff/g.  The "g" at
> the end allows sed to change all occurances rather than
> just the first.
>
> For example:
>
>    $ echo Novalug | sed 's/lug/LUG'
>    NovaLUG
>
> The "existing stuff" part can be a regular expression.
>
> What would be the output of:
>
>    echo NovaLUG | sed 's/X*/,/g'
>
> Jon