I ran across this in the Perl cook book .
Every program starts out with three global filehandles already opened: STDIN, STDOUT, and STDERR. STDIN (standard input) is the default source of input, STDOUT (standard output) is the default destination for output, and STDERR (standard error) is the default place to send warnings and errors. For interactive programs, STDIN is the keyboard, STDOUT and STDERR are the screen: 
while (<STDIN>) {                   # reads from STDIN
    unless (/\d/) {
        warn "No digit found.\n";   # writes to STDERR
    }
    print "Read: ", $_;             # writes to STDOUT
}
END { close(STDOUT)                 or die "couldn't close STDOUT: $!"
+ }

[download]

In reply to Re: top and STDERR hell... by crusty_collins
in thread top and STDERR hell... by DouglasDD

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.