Hi, I have just tried the following code:

use strict;
use warnings;
use constant MAXBYTES => scalar 5;

my $result;

$| = 1;
MSG: 
    print "Please be aware maximum length 255 characters!:\n"; 
    
do {
    print "Send this text to clients:\n\n";
    chomp ($result = <STDIN>);
    if (length($result) >= MAXBYTES) {
    print "\nYou have reached the limit of characters ".length($result
+)."!\n\n";
    goto MSG;
    }
} until ($result eq "END" or $result eq "end");
$| = 1;
[download]

and it works as expected for me: it loops when I enter strings such as "foo" or "bar" and exits the loop if I enter "end" or "END".

Having said that, there are a few problems in this code. One is that the message states:

print "Please be aware maximum length 255 characters!:\n";
[download]

but MAXBYTES is set to 5. The second one is the use of goto, this is widely considered to be a very bad programming practice, especially when the goto brings you upward in your code and out of a loop, and this is pretty useless in this case. Try something like this instead:

use strict;
use warnings;
use constant MAXBYTES => scalar 5;

my $result;

$| = 1;
my $msg = "Please be aware maximum length 255 characters!:\n"; 
    
do {
    print "Send this text to clients:\n\n";
    chomp ($result = <STDIN>);
    if (length($result) >= MAXBYTES) {
         print "\nYour input has a length of " . length($result) . "; 
+the limit is ". MAXBYTES, "\n\n";
         print $msg;
    }
} until (uc ($result) eq "END");
$| = 1;
[download]

although this is still somewhat clunky (but I wanted to stay close to your code). One additional question: why are you setting $| twice to the same value?

On the problems with the goto function, please read this classical text: http://www.u.arizona.edu/~rubinson/copyright_violations/Go_To_Considered_Harmful.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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

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:
	&		&
	<		&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.