perl -aF: -ne 'chomp @F;push @{$h{$F[0]}},$F[2]}{print join(":",$_,@{$
+h{$_}}),"\n" for sort keys %h'
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Are we going for golf?    :-)

echo "China:wd:2
Japan:wd:6
China:sg:2
Japan:sg:10
China:kng:70
Thailand:kng:6" | perl -F: -le'push@{$h{$F[0]}},$F[2]}{$,=":";print$_,
+@{$h{$_}}for sort keys%h'
China:2:2:70
Japan:6:10
Thailand:6
[download]