Awk命令总结 | Zhangshun Blog👌

Linux 系统的两个神级工具：sed 和 awk，算是运维平时工作中最常用的工具了，所以有必要更加深入的学习一下了。 #### Awk 用例:log.txt ``` 2 this is a test 3 Are you like awk This's a test 10 There are orange,apple,mongo ``` **Ⅰ、普通输出** ``` [root@node2 awk]# awk '{print $1,$4}' log.txt 2 a 3 like This's 10 orange,apple,mongo ``` **Ⅱ、格式化输出** ``` [root@node2 awk]# awk '{printf "%s|%s\n",$1,$4}' log.txt 2|a 3|like This's| 10|orange,apple,mongo ``` ``` [root@node2 awk]# awk '{printf "%02s %-2s %-20s %-20s %s\n",NR,$1,$2,$3,"1"}' log.txt 1 2 this is 1 2 3 Are you 1 3 This's a test 1 4 10 There are 1 %[flags][width][.precision]conversion % - 5 .2 f - %是必须的, 任何格式符都由百分号开始 - flags 是可选的,详见下表 - width 是可选的, 表示输出的宽度 - precision 可选的, precision 依赖于 conversion, 详见下表. - conversion 是必须的, 表示如何格式化参数, 详见下表 conversion：%s——>字符串，%d——>十进制整数 flags：0——>数字前面补0 ``` **Ⅲ、-F，按照指定字符分割** ``` [root@node2 awk]# awk -F, '{print $1,$2}' log.txt 2 this is a test 3 Are you like awk This's a test 10 There are orange apple ``` **Ⅳ、变量NR，表示当前处理的是第几行** ``` [root@node2 awk]# awk '{print NR")" $1}' log.txt 1)2 2)3 3)This's 4)10 ``` **Ⅴ、内置函数tolower()、toupper()、length()** ``` [root@node2 awk]# awk '{print tolower($0)}' log.txt 2 this is a test 3 are you like awk this's a test 10 there are orange,apple,mongo ``` ``` [root@node2 awk]# awk '{print toupper($0)}' log.txt 2 THIS IS A TEST 3 ARE YOU LIKE AWK THIS'S A TEST 10 THERE ARE ORANGE,APPLE,MONGO ``` ``` [root@node2 awk]# awk '{if (length($1)==1) print $0}' log.txt 2 this is a test 3 Are you like awk ``` **Ⅵ、awk '条件动作' 文件名，允许指定输出条件，只输出符合条件的行** ``` [root@node2 awk]# awk '/is/ {print $1,$3}' log.txt 2 is This's test ``` 上面代码中，print命令前面是一个正则表达式，只输出包含is的行 下面的例子只输出奇数行，以及输出第二行以后的行 ``` [root@node2 awk]# awk 'NR%2==1 {printf "%s\t%s\n",$1,$2}' log.txt 2 this This's a [root@node2 awk]# awk 'NR>2 {printf "%s=====%s\n",tolower($1),toupper($2)}' log.txt this's=====A 10=====THERE ``` **Ⅶ、if语句** 格式：`awk '{if (条件) print $1,$2}' $filename` ``` [root@node2 awk]# awk '{if ($1==2) printf "%s====%s\n",$1,$2}' log.txt 2====this [root@node2 awk]# awk '{if (NR>2) printf "%s~~%s\n",$1,$2}' log.txt This's~~a 10~~There [root@node2 awk]# awk '{if ($NF=="awk") printf "%s==%s==%s==%s\n",$1,$2,$3,$4}' log.txt 3==Are==you==like ``` 格式：`awk '{if (条件) print $1,$2;else print "----"}' $filename` ``` [root@node2 awk]# awk '{if ($1==2) print $0;else print "---"}' log.txt 2 this is a test --- --- --- [root@node2 awk]# awk '{if ($NF=="awk") print $0;else print "---"}' log.txt --- 3 Are you like awk --- --- ``` **Ⅷ、awk的运算符** 关系运算符：<、<=、>、>=、!=、== 逻辑或：|| 逻辑与：&& 赋值语句：=、+=、-=、*=、/=、%=、^=、**= 匹配正则表达式和不匹配正则表达式：~、!~ **Ⅸ、字符串匹配** ``` [root@node2 awk]# awk '$1~/This/ {print $0}' log.txt This's a test [root@node2 awk]# awk '$NF~/est/ {print $0}' log.txt 2 this is a test This's a test [root@node2 awk]# awk '$NF!~/apple/ {print $0}' log.txt 2 this is a test 3 Are you like awk This's a test #同时匹配两个 [root@node2 awk]# awk '$NF~/mongo|awk/ {print $0}' log.txt 3 Are you like awk 10 There are orange,apple,mongo ``` **Ⅹ、BEGIN{}、{}、END{}，意味着执行前、执行中和执行后的意思** ``` $ cat score.txt Marry 2143 78 84 77 Jack 2321 66 78 45 Tom 2122 48 77 71 Mike 2537 87 97 95 Bob 2415 40 57 62 ``` awk脚本如下： ```shell $ cat cal.awk #!/bin/awk -f #运行前 BEGIN { math = 0 english = 0 computer = 0 printf "NAME NO. MATH ENGLISH COMPUTER TOTAL\n" printf "---------------------------------------------\n" } #运行中 { math+=$3 english+=$4 computer+=$5 printf "%-6s %-6s %4d %8d %8d %8d\n", $1, $2, $3,$4,$5, $3+$4+$5 } #运行后 END { printf "---------------------------------------------\n" printf " TOTAL:%10d %8d %8d \n", math, english, computer printf "AVERAGE:%10.2f %8.2f %8.2f\n", math/NR, english/NR, computer/NR } ``` 来看一下执行结果：(也可以这样运行 ./cal.awk score.txt） ``` $ awk -f cal.awk score.txt NAME NO. MATH ENGLISH COMPUTER TOTAL --------------------------------------------- Marry 2143 78 84 77 239 Jack 2321 66 78 45 189 Tom 2122 48 77 71 196 Mike 2537 87 97 95 279 Bob 2415 40 57 62 159 --------------------------------------------- TOTAL: 319 393 350 AVERAGE: 63.80 78.60 70.00 ``` #### 参考 [AWK 简明教程](https://coolshell.cn/articles/9070.html)