I see a couple of answers like this: 

$ echo " x x x x x x x x
x x x x
 x x x x x x x x x" | perl -pe's/x/o/g && ++$c }{ print "Count = $c\n"
+'
Count = 3

[download]
$ echo " x x x x x x x x
x x x x
 x x x x x x x x x" | perl -pe'if ( s/x/o/g ) { ++$c } }{ print "Count
+ = $c\n"'
Count = 3

[download]

That don't accurately count replacements. Use the return value from s///g: 

$ echo " x x x x x x x x
x x x x
 x x x x x x x x x" | perl -pe'$c += s/x/o/g }{ print "Count = $c\n"'
Count = 21

[download]

In reply to Re: user input Regular Expression by jwkrahn
in thread user input Regular Expression by Saved

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.