open IN, "r1.dat"; open OUT, ">r1.txt"; $/=undef; $line=; while ($line=~m/([123]?[.s]*[a-z\=.]+)/oi) { $book=$1; print $book,"n"; $t_book=$book; $t_book=~s/.//g; $t_book=~s/\l=([a-z]+)\/$1/ig; $t_book=~s/<(|/)(B|I|SC|U)>//ig; $quote=bibref($t_book); if($quote) { $line=~s/($book)/$1/ig; } } print OUT $line; close(IN);