+#---------- useful stuff ----------
+
+sub pipeval ($@) {
+ my ($val, @cmds) = @_;
+ my (@pids);
+
+ my $paste_child= open PIPEVAL_PASTE, "-|";
+ defined $paste_child or die $!;
+ if (!$paste_child) { print $val or die $!; exit 0; }
+
+ my $f= 'PIPEVAL_PASTE';
+
+$_=<$f>;
+print STDERR ">$_<\n";
+
+ foreach my $cmd (@cmds) {
+ my $newf;
+print STDERR "$cmd | $f\n";
+ push @pids, open2($newf, "<& $f", $cmd);
+# if (@pids>1) { close $f or die $!; }
+print STDERR "$cmd | $f $newf @pids\n";
+ $f= $newf;
+ }
+
+ $!=0; { local ($/)=undef; $val= <$f>; }
+ defined $val or die $!;
+ $f->error and die $!; close $f or die $!;
+
+ waitpid($paste_child,0) == $paste_child or die "paste $? $!";
+ $?==0 or $?==13 or die "paste $?";
+ close PIPEVAL_PASTE or die $!;
+
+ foreach my $cmd (@cmds) {
+ my $pid= shift @pids;
+ waitpid($pid,0) == $pid or die "$pid $? $!";
+ $?==0 or $?==13 or die "$cmd $?";
+ }
+ return $val;
+}
+