$1.$ Use I$/$O redirection in combination with the grep, head $,$ and tail commands to perform the tasks described below. You must complete these tasks in the order specified.

a$.$ Find out where the sequence with the description yffB can be found in the FASTA file dna$1.$fasta, as obtained in the previous problem statement, and write this information to the terminal. If the FASTA file dna$1.$fasta cannot be found, then the error message needs to be discarded $($i$.$e$.,$ the error message cannot be written to the terminal, and it cannot be written to a text file$).$

b$.$ Based on the location of the sequence yffB you just found, find the location of the next sequence.

Hint: Exclude the description line $($that is$,$ the line starting with $>)$ of the sequence yffB and count its nucleotide lines.