extract sequences from multifasta file by ID in file using awk

Question

I would like to extract sequences from the multifasta file that match the IDs given by separate list of IDs.

FASTA file seq.fasta:

>7P58X:01332:11         


        

Answer 1

$ awk -F'>' 'NR==FNR{ids[$0]; next} NF>1{f=($2 in ids)} f' id.txt seq.fasta
>7P58X:01332:11636
TTCAGCAAGCCGAGTCCTGCGTCGTTACTTCGCTT
CAAGTCCCTGTTCGGGCGCC
>7P58X:01334:11613
ACGAGTGCGTCAGACCCTTTTAGTCAGTGTGGAAAC

Answer 2

Following awk may help you on same.

awk 'FNR==NR{a[$0];next} /^>/{val=$0;sub(/^>/,"",val);flag=val in a?1:0} flag' ids.txt  fasta_file