Hi michael.kitchen,

You've been shown how to sort in Perl.

An alternate solution might be to use the sort program probably provided by your operating system and to pipe the output to your Perl program, which would then have to read from the standard input, with something like while (my $line = <>) { ....

The shell command would be something like this:

$ sort [-options] books/bookLIST.txt | perl your_program.pl
[download]

I'm doing that quite often because I'm dealing with files which are too large to fit into memory, so using the OS sort utility (which knows well how to deal with very large files) is quite convenient.