[Administrator@mc-win@/cygdrive/e/SoftWares/Project/log/click/2017-03-17@10:33:49]
517 $ time awk '{print NR}' click.log_2017-03-17T04|tail -n1
116570
real 0m2.535s
user 0m1.499s
sys 0m1.093s
[Administrator@mc-win@/cygdrive/e/SoftWares/Project/log/click/2017-03-17@10:34:11]
518 $ time wc -l click.log_2017-03-17T04
116570 click.log_2017-03-17T04
real 0m19.201s
user 0m17.640s
sys 0m0.078s
[Administrator@mc-win@/cygdrive/e/SoftWares/Project/log/click/2017-03-17@10:34:38]
519 $ time awk 'END{print NR}' click.log_2017-03-17T04
116570
real 0m0.375s
user 0m0.343s
sys 0m0.031s
[Administrator@mc-win@/cygdrive/e/SoftWares/Project/log/click/2017-03-17@10:35:22]
520 $ time grep -n "" click.log_2017-03-17T04|awk -F: '{print '}|tail -n1
grep: bad regex '': empty (sub)expression
real 0m0.084s
user 0m0.030s
sys 0m0.030s
[Administrator@mc-win@/cygdrive/e/SoftWares/Project/log/click/2017-03-17@10:36:15]
521 $ time grep -n "" click.log_2017-03-17T04|awk -F: '{print }'|tail -n1
grep: bad regex '': empty (sub)expression
real 0m0.082s
user 0m0.030s
sys 0m0.015s
[Administrator@mc-win@/cygdrive/e/SoftWares/Project/log/click/2017-03-17@10:36:25]
522 $ time sed -n '$=' click.log_2017-03-17T04
116570
real 0m0.885s
user 0m0.546s
sys 0m0.046s
總結 ： time awk 'END{print NR}' click.log_2017-03-17T04
執行最快，是 wc -l file 的幾十倍的效率！！
還有 cat test1.sh |wc -l
這種就不要測試了，會把CPU用壞的吧！
time grep -n "" click.log_2017-03-17T04|awk -F: '{print }'|tail -n1
這個是人家博客寫錯了，正確的是：
time grep -n "" click.log_2017-03-17T04|awk -F: '{print $1}'|tail -n1
表示只是截取行號
上述grep 命令要求其支持""作為查找模式，windows上的busybox 1.6版的grep不支持該功能。linux支持:
[root@mc-click@/home/share@11:00:07]
2019 $ time awk 'END{print NR}' click_oom
250
real 0m0.013s
user 0m0.000s
sys 0m0.001s
[root@mc-click@/home/share@11:00:36]
2020 $ time grep -n "" click_oom |awk -F: '{print $1}'|tail -n1
250
real 0m0.004s
user 0m0.004s
sys 0m0.003s
作者：五大RobertWu伍洋
鏈接：https://www.jianshu.com/p/b18a1b40ea05
來源：簡書
簡書著作權歸作者所有，任何形式的轉載都請聯系作者獲得授權並注明出處。