linux---三剑客

linux三剑客
一：awk取列
   awk ‘{print $1 “ ” $2}’ old.txt
二：sed取行
   sed –n ‘1,2px’ old.txt
三：grep删选
   grep 排除aaa
   grep –v ‘aaa’ old.txt
   grep 只留aaa
   grep aaa old.txt