Yikes! That code didn't get wrapped for some reason, and it's throwing the navigation table way off kilter. Anyway.

The code you posted is really Perl 4 style, with a whole whack of arrays instead of the Perl 5 style Array of Arrays (or AoA as you will hear more often). AoA is a much easier way to implement what you have done. Easier is better, no?

I would define your input file format, first, in a structure, and then write a loop to use this information to re-parse the file. Consider making an array that has only the start positions of each of the fields:

     # Define the format of the file
     my (@file_format) = (
           0,
           3,
          53,
          60,
          67,
          74,
        # etc.
        241+169, # Last position, presumably
     );
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Now the length of each field $n, for substr() purposes, at least, is simply $file_format[$n+1] - $file_format[$n]. Note that the last entry in the table shouldn't be used, that is, $n should only go as high as $#file_format-1.

Now you can put each line into an array as you read it in, and then write it to a file straight away. Just open both files at the same time using two different filehandles, such as IN_FILE and OUT_FILE. You are putting your data into temporary arrays, but since the data is only used exactly once.

     my (@field_data);
     for (my $i = 0; $i < $#file_format; $i++)
     {
           $field_data[$i] = substr($_,
                                    $file_format[$i],
                                    $file_format[$i+1]-
                                    $file_format[$i]);
           # Clean up as required, by trimming
           $field_data[$i] =~ s/\s+$//;
     }
     print OUT_FILE join('|', @field_data);
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If you want, you can use unpack instead, but apart from stylistic differences, there is no real point unless you need maximum speed (i.e for 5 million line files, or what have you).