Question about patterns

[Steven W. Orr]

I may be wrong, but I think there's a way to do what I want without using a 
regex.

I have a file called foo-1.2-3.tar.gz
I need to set a variable equal to
foo-1.2-i386-x86_64-3.tar.gz

Is there a way to do this without parsing my brains out? I am facile with the 
variable operations like # ## % %% and /, but what I really want to do is to 
say something like

bar=${foo/-([1-9]).tar.gz/-i386-x86_64-\1.tar.gz}

where the \1 is some sort of thing that I can use to refer to a backref. Does 
this exist in bash or do I just do it with a regex?

TIA :-)

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