When learning any language, Perl or otherwise, it is vital to have a handy desk reference. I have found Programming Perl to be the book of choice for me, and many others, as it provides a function-by-function breakdown of what stuff does. A good portion of this is also available in 'perldoc', if you happen to have access to that. As in, 'perldoc -f seek', which would return:

seek FILEHANDLE,POSITION,WHENCE

Sets FILEHANDLE's position, just like the fseek call of stdio. FILEHANDLE may be an expression whose value gives the name of the filehandle. The values for WHENCE are 0 to set the new position to POSITION, 1 to set it to the current position plus POSITION, and 2 to set it to EOF plus POSITION (typically negative). For WHENCE you may use the constants SEEK_SET, SEEK_CUR, and SEEK_END (start of the file, current position, end of the file) from the Fcntl module. Returns 1 upon success, 0 otherwise.

The moral of the story is if you ever stumble across something you "don't understand", don't just paste it in there, read up on it until you have a handle on what it does, at least in theory.

Unlike, say, advanced particle physics where there is an element of the unknown, Perl is very well documented and there is little left to mystery. Cargo Cult Programming is not a productive way to learn.