你那樣做操作很慢
而且看起來不簡潔
如果你非要這樣做,試試
echo $((`free | head -3 | tail -1 | awk '{printf $3}'`*100/`free | head -2 | tail -1 | awk '{printf $2}'`))??????????????????????????????????????????????????????????????????????????????????????л????????????????????????????????????????С??????λ???????????$(( ))??linux??????????????????????????λС??????????echo "scale=2;`free | head -3 | tail -1 | awk '{printf $3}'`*100/`free | head -2 | tail -1 | awk '{printf $2}'`"|bcscale=2 ;.....|bc #???λС??