I have a very large file to read, so when I use while for reading it line by line, the script starts taking more time to read the line as I dig deep in the file; and to mention the rise is exponential.

while (<$fh>)
{do something}

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Does while has to parse through all the lines it has already read to go to the next unread line or something like that? How can I overcome such a situation?

EDIT 1

@perlholic has posted my code

And I want to add that i have tested the timing for each step individually but all are linear except when I read anew line from the file

Thanks in advance

In reply to How does the while works in case of Filehandle when reading a gigantic file in Perl by raj4489

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