our @data=<DATA>;
 
# some code comes here...
sub dosubstr {
   foreach my $i ( 0..$#data ) {
      my $line=$data[$i];
      my $jcpu=substr($line,2,16);
      my $j=substr($line,18,48);
      my $s=substr($line,290,16);
      $jcpu =~ s/\s//g;
      $s =~ s/\s//g;
      $j =~ s/\s//g;
      #  warn "$jcpu $j $s";
      # ..store the values in a hash, but that is not important here
      }
   }
 
sub doregex {
   foreach my $i ( 0..$#data ) {
      my $line=$data[$i];
      $line =~ m/^04(?=(\S+)).{16}(?=(\S+)).{40}.{216}.{16}(?=(\S+)).{16}/ ;
      my $jcpu=$1;
      my $j=$2;
      my $s=$3;
      #  warn "$jcpu $j $s";
      # ..store the values in a hash, but that is not important here
      }
   } 

__DATA__
04A12345          RELEASE
 
                A12345          RELEASE         A12345
04FTOP            DD_BUIL+
 
        
        FTOP            DD_REKL+        FTOP
04FTOP            DD_PLAN+
 
                FTOP            DD_REKL+        FTOP