perl script for nref

gunzip -c NREF.xml.gz | perl -e 'while(<>){if($_=~ /^$1\n"}elsif($_=~/^/){$line=<>;while($line !~ /<\/sequence>/){print$line;$line=<>;}}}' > NREF.fasta

as you may have noticed, the new website is out and NREF is not there amymore, since UniRef100 now replace it.

<> : 행입력연산자(null file handle 사용) 표준입력(STDIN)으로부터 입력받음, pipe(|)등을 사용하여 filter 프로그램 작성 가능
$_ : 전역특수변수(globa special variable), while loop에서만 사용 가능