If you just want to print the lines containing a particular keyword, then the method you're using is probably the best: It's clear, easy to maintain, and unless you're doing a large amount of processing on very large files, is likely fast enough, to boot.

However, it's possible to do so without reading the file line-by-line. You could do it this way:

$ cat t.pl
#!/usr/bin/perl
use strict; use warnings;
my $t;
{ # A: Slurp in the entire file
    local $/;
    $t = <DATA>;
}

# B: Scan the entire file for a lines containing either
# of the words 'fox' or 'wood', and print them.                       
+         
print "<$_>\n" for $t=~/^(.*?(?:fox|wood).*?)$/gm;
__DATA__
Now is the time for all good
men to come to the aid of their
party.  The quick red fox jumped
over the lazy brown dog. How much
wood can a woodchuck chuck?  If
a woodchuck could chuck wood?

$ perl t.pl
<party.  The quick red fox jumped>
<wood can a woodchuck chuck?  If>
<a woodchuck could chuck wood?>

[download]

You'll want to read perldoc perlre for the details of the regular expression used. In it, I use two features that I only use rarely.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

In reply to Re: Printing th entire line with a keyword by roboticus
in thread Printing th entire line with a keyword by Anonymous Monk

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.