Your problem is that the
while (<F>) will only read a single line, and your
emp and /emp do not occure on the same line.
To do what you are trying to do here you could use local $/; before the while, to make Perl slurp in the whole data as one line. You will also need to alter the regex to use the s option ( which also has an extra paren at the end ):
$_ =~m/(<emp>.*<\/emp>)/s;
The
/s says (simplified) to treat the whole string as a single line -- don't stop patterns at the newlines.
Of course if you are doing more than just toy-work with XML you might want to check out www.cpan.org and check out the libraries available there.