it seems pretty much that this is what I was looking for.
I was mentally bound to the idea of froking a new kid for each client and therefore I was thinking of forking another kid that reads the file(s) and sends them to all other client-kids. But this seems to me too complicated for Perl, Perl is smarter (than me). But thank Good, that there are guys like you :-)

I'll soon will try your solutions.
For now thanks a lot,
Carl

from your code I was able to go on, thanks for this nice push. I packed the Server & Handle stuff in one package having in mind that I might be able to listen for new clients within a spawned kid and pass the updated valid client-handles to its parent.

But this failed and want to ask now:

is there a way to pass those handels or the updated class var.: @CL (which contains all client-handles) to another process?

package SoServ; #: one server for all clients

    use IO::Socket::INET;
    use IO::Select;
    my @CL = (); #: array of sock.Handles to Clients
    my $S; #: Socket-Server
    my $H; #: for IO::Select

    sub new { #: new Socket-Server
        my $me = {};
        $me->{'a'} = shift; #: loc.Adddress address
        $me->{'p'} = shift; #: port to connect
        $S = IO::Socket::INET->new(
                LocalAddr => $me->{'a'},
                LocalPort => $me->{'p'},
                Proto     => 'tcp',
                Listen    => 1,
                Reuse     => 1,
                Timeout   => 60
                );
            die "Can't create SoServ ($!)\n\n" unless $S;
        $H = IO::Select->new();
        $H->add($S);
        return bless $me;
    }

    #: wait for new connections
    sub waitNewConn { 
        my $me = shift;
        #: either endless (1) or just 2 clients (0):
        my $withKids = shift; 
        while (1) { # endless Loop if with Kids!
            # wait timeout-sec and then try again:
            my $newCL = $S->accept() || next; 
            print $newCL "Hi, guy, nice meeting you\n";
            $H->add($newCL);
            #update @CL instead of:push @CL,$newCL;
             @CL = $H->can_write(1); 
            # no kid: return after 2 conn.
            return @CL if (@CL == 2 && !$withKids); 
        } # while (1)
    } # sub

    sub clients { return @CL }


#######   end packages   #############

package main;

    my $addr = 'localhost'; # hard coded for now
    my $port = 2345;        # dito
    my $Serv = SoServ::new( $addr,$port ); # start Server

# Array of Handles to Clients derived from SoServ->@CL
    my @Clients = (); 

    my $withKids = 1; # want kids or everyth. in 1 process?

    if ($withKids) {
        spawn($Serv); # kid is waiting for new Clients
    } else {
        # no kid, waiting here for new (2) Clients
        @Clients = $Serv->waitNewConn(0); 
    }

    my $line = '';
    my $f = '/home/cas/Data/sp1Min/spAdj.dta';
    my $n = 9; # just 9 lines for now
    open(SP, "< $f") or die "can't open SP: $f: $!"; #

    while (defined($line = <SP>)) {
        print $line; # control
        @Clients = $Serv->clients() if ($withKids);
        for (@Clients) {
            print $_ $line;
        }
        last if (!$n--);
    }
    close(SP);
exit;

    sub spawn {
        my $S = shift;
        my $pid;
        if (!defined($pid = fork)) {
            print "cannot fork: $!";
            return;
        } elsif ($pid) {
            print " I'm the Server-Parent: pid:$pid \$\$:$$\n";
            return; # I'm the parent
        }
        $S->waitNewConn(1); # yes with Kids, of course => (1)
        exit;
    } # end sub spawn
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