[galaxy-user] How to filter the sequences containing not[ATCG] character？

Hi Jen,As the title, I have a [fasta] file that obtained from a [gtf] file,

cuff102.1atcgtaaagggcgat>cuff103.1gtcgttgactNNNNNNNNgtc and I want to get the output like this to filter the sequences that contain any not[ATCG] character? cuff102.1atcgtaaagggcgat I have a large of sequences to filter. I thought a way that firstly convert the file to [interval] file, and secondly SELECT the line not matching the patten /\t[ATCGatcg]*[^ATCGatcg]/.Am I right? Or there is a one-step way ?