Like pc88mxer already said, you need to know when to stop to read. Your code

@resp = <$s>; # expect one line response
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will read from $s until your daemon stops or closes the socket, contrary to your comment that it will only read one line. Try it with the following code:

@resp = ();
while (defined $_ = <$s> and ! /^\s*$/) {
    warn "DEBUG: Got >$_<";
    push @resp, $_;
};
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The above loop will output some debug information and read until the next empty line. If something goes wrong, you will easily see that from the debug information ...