# called from sub foobar() which in turn
# is called from foo() which in turn...
sub do_something {
... 
try {
	stuff();
} catch Error::Sys with {
        # handly any System error right here
};
# any other error will go up the call tree..

}

##</code><code>##

# called from sub foobar() which in turn
# is called from foo() which in turn...
sub do_something {
... 
eval {
	stuff();
};
my $err = $@;
if ($err =~ m/SYSTEM:/) {
        # handle any System error right here

} elsif ($err) {
	# any other error will go up the call tree..
	die $err; # rethrow
}

}