[galaxy-user] Galaxy Question

Hello, I would like to use Galaxy to divide a very large Ilumnia fasta file (~3GB) into separate fasta files. Is this possible on Galaxy? Here is an example of the reads:

HWI-ST156:535:C10GLACXX:8:1101:1195:1080 1:N:0:CGGTTGT AAATAGAATATCACATTAAAATCACAAGCAGGACAGTGTGTGTAAAAGAAATCTTTTGTGAATTCAACGTTTATCAATTAGANNNNACGCCTACGTGTAG

HWI-ST156:535:C10GLACXX:8:1101:1210:1102 1:N:0:CGGTTGT ATTTATCATAACAACTTAAATCAGTCAGTGGATTTCTGTCGGTCCGGTTAGCTCGGTTGGTAAAGGCGTTTGTTCGATCGTCTGTATTTTGCAATCGGGC

I have tried the "Filter and Sort" option to try and select sequences just by a beginning sequence (ATGC, for example) to separate these sequences into a specific file, but I have been unsuccessful in this. Thank you, Dominique