eof FILEHANDLE
       eof ()
       eof     Returns 1 if the next read on FILEHANDLE will
               return end of file, or if FILEHANDLE is not open.
               FILEHANDLE may be an expression whose value gives
               the real filehandle.  (Note that this function
               actually reads a character and then "ungetc"s it,
               so isn't very useful in an interactive context.)
               Do not read from a terminal file (or call
               "eof(FILEHANDLE)" on it) after end-of-file is
               reached.  File types such as terminals may lose
               the end-of-file condition if you do.

##</code><code>##

               Practical hint: you almost never need to use "eof"
               in Perl, because the input operators typically
               return "undef" when they run out of data, or if
               there was an error.

##</code><code>##

while (<STDIN>) {
    print;
    print "***\n";
}

##</code><code>##

while (<STDIN>) {
    print $_, "***\n";
}