You didn't specify that the file had fixed length fields - though I see now from your code that it probably does - so I went and wrote the following: 
use strict;

my ($handle, $c, $rand, %hash, @lines);

open($handle, "random.txt");
for (<$handle>) {}   # Number of lines in file
while ($c < 10) {            # now put into $.
    $rand = int rand($.);
    if (!$hash{$rand}) {      # Get 10 unique,
        $hash{$rand} = 1; $c++;
    }                    # random line numbers
}
seek($handle, 0, 0); $. = 0;      # Reset file
while (<$handle>) {          # Retrieve chosen
    if ($hash{$.-1}) {                 # lines
        chomp; push(@lines, $_);
    }
}
for ($c = @lines; --$c;) {     # Shuffle lines
    my $rand = int rand ($c+1);
    @lines[$c,$rand] = @lines[$rand,$c];
}
print "$_\n" for (@lines);     # Display lines
close($handle);

[download]
Disregard if your file has fixed-length fields.

In reply to Re: reading a particular line in a large text file by TedPride
in thread reading a particular line in a large text file by fadingjava

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.