I have a large text file 130,000 lines (5mega).
I want to add all lines starting with 5 same letters
eg "abcde" and ending with the letters "partname" into
a new file.
I am using a "foreach" reading line by line and doing
a match---it works but is very slowwwwwww!
I need something more fancy!!! 
open C, ">c:\\somefile.txt";
open (FH, "k:\\1\\somefile.txt") || die "Couldn't  open file: $!";
@required=();
@all=<FH>;
foreach $item (@all) {
  next unless (index($item, 'abcde') == 0);

  if ($item=~/abcde.*PARTNAME/) {
    push (@required,$item);
  }
}
print C @required;

[download]

2005-01-12 Janitored by Arunbear - added code tags, as per Monastery guidelines

In reply to looking for speed!! large file search and extract by smbs

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.