I'll tell you to read this :-)

perldoc perl
perldoc -f open
perldoc -f read
perldoc -f binmode
perldoc -f pack
perldoc -f unpack
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As for books, you might try 'Learning Perl' or dive in at the deeper end and get 'Programming Perl' (the 3rd edition is a little easier for novices than the first 2). Both books are published by O'Reilly.

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.
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