the "diamond" operator <> attempts to read a line from the file whose name you pass on the command line. (e.g. ./myscript.pl file.txt) If you pass more than one filename on the command line, it will loop over all the lines in each file.

Read up on <> in perldoc perlop

If it runs out of command-line arguments and you try to read from it, then it attempts to read from STDIN (in this context, the keyboard). What your code is doing is reading in the file once, on the first pass. You think it's going to read it again when you say  while ( <> ) {, but what it's actually doing is attempting to read another file whose name was passed to it on the command line. But there is no such thing, so it just sits there expecting input from the keyboard (Control-D is the symbol for "end of file", so try hitting that a few times and see what happens).

Moral of the story: don't do it that way =) Loop through the file *once* and do all your counting on that one run through it.

HTH 

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'

[download]

In reply to (arturo) Re (3) : New perl student... feeling stupid by arturo
in thread New perl student... feeling stupid 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.