grep the filename using sed

I have the following line

result_0.01.dat resultFile

I would like to get and change just the (result_0.01) part to a different text which might include numbers. Preferably I would like this to be done using sed.

Thank you in advance.

Answer

echo "result_0.01.dat resultFile" | sed  "s|.*.dat|someOtherText.dat|g"

what happens here in sed part is:

we substitude (s flag at the beginning of sed) we find everything till .dat. We replace that part with someOtherText. and we do it globally (g flag at the end)