If you want to match a line in a multiline string, you need the m-modifier and the line-begin (^) and line-end ($) indicator.
You can read about those in the perldocs already meantioned.

Going with your specification so far:

I need to extract "10" however there might be 2 or 3 words preceding.
and
a very large multi line string, and only one line looks likt describe

Going with this, i would suggest:

$str =~ /^(?:\w+\s+){2,3}10$/m

There might be other restrictions you want to place on your match (more specific whitespace preceding the 10? optional whitespace (or even other words) after the 10?)

We don't know. You have to make up your mind, what the appropriate pattern is.

In reply to Re^2: regexp: extracting info by pKai
in thread regexp: extracting info by jeanluca

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.