[cobalt-developers] integrate the date in a filename?

["[Can-Host Networks] Félix C.Courtemanche" <webmaster@xxxxxxxxxxxx>]

Hello,

I have been working a lot on my raqs lately to backup about every important
info (because of my previous experience... DNS fail about once per 2 months
wich means you have to redo it all)

Now, my question is:
how would I "integrate" the date automatically in a filename?

I already have the date format that I want: "date +%Y.%m.%d"
I would like the result to be something like:
file.[date].tar

so... I create my tar file easily but I don't know how to make the real date
appear instead of "date +%..."
Anyone have an idea?
Note... I knwo how to do that in php or perl, but my goal is to find out in
ssh instead of using any language.
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