awk分类求最大值和最小值

被操作文件内容：
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ex:awk '{if(max[$1]==0){max[$1]=$2};if(min[$1]==0){min[$1]=$2};a[$1]++;
max[$1]=(max[$1]>$2? max[$1]:$2);min[$1]=(min[$1]<$2?min[$1]:$2)};
END{for(i in a){print i ,max[i],min[i]}}'