The FAQ method is more efficient because it is reading in fixed block sizes which it doesn't have to split into lines.

Here is a benchmark to show the difference. I added wc for comparison: 

    $ time wc -l bigfile
      91420 bigfile

    real    0m0.016s
    user    0m0.010s
    sys     0m0.006s


    $ time perl faq.pl bigfile
    91420

    real    0m0.032s
    user    0m0.027s
    sys     0m0.004s

    $ time perl cody.pl bigfile
    91420

    real    0m0.105s
    user    0m0.098s
    sys     0m0.008s

[download]

Here is the way I usually don't do it, this is twice as slow as the slowest method above:     perl -le 'print $==()=<>' file

--
John.

Update: Added benchmark.

In reply to Re: How To Count Lines In File? by jmcnamara
in thread How To Count Lines In File? by Cody Pendant

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.