Linux-AWK命令

参考菜鸟教程

简介

AWK 是一种处理文本文件的语言，是一个强大的文本分析工具。

之所以叫 AWK 是因为其取了三位创始人 Alfred Aho，Peter Weinberger, 和 Brian Kernighan 的 Family Name 的首字符。

语法

awk [选项参数] 'script' var=value file(s)
或
awk [选项参数] -f scriptfile var=value file(s)

基本用法

用法1 awk '{[pattern] action}'

每行按空格或TAB分割，输出文本中的1、4项

[root@node1 ~]# cat log.txt 
2 this is a test
3 Are you like awk
This's a test
10 There are orange,apple,mongo
[root@node1 ~]# awk '{print $1, $4}' log.txt  # 行匹配语句 awk '' 只能用单引号
2 a
3 like
This's 
10 orange,apple,mongo
[root@node1 ~]#
[root@node1 ~]# awk '{printf "%-8s, %-10s\n", $1, $4}' log.txt  # 格式化输出
2       , a         
3       , like      
This's  ,           
10      , orange,apple,mongo

用法2 awk -F

awk -F #-F相当于内置变量FS, 指定分割字符

使用多个分隔符.先使用空格分割，然后对分割结果再使用","分割

[root@node1 ~]# cat log.txt 
2 this is a test
3 Are you like awk
This's a test
10 There are orange,apple,mongo
[root@node1 ~]# awk -F '[ ,]' '{print $1,$2,$5}' log.txt 
2 this test
3 Are awk
This's a 
10 There apple

用法3 awk -v

awk -v # 设置变量

定义了两个变量，一个是a=1，一个是b=s

[root@node1 ~]# awk -va=1 -vb=s '{print $1, $1+a, $1b}' log.txt 
2 3 2s
3 4 3s
This's 1 This'ss
10 11 10s

运算符

例子: 过滤出第一列大于2，并且第二列等于Are的

[root@learn200 ~]# awk '$1>2 && $2="Are" {print $1,$2,$3}' log.txt 
3 Are you
This's Are test
There Are orange,apple,mongo

正则匹配

~ 表示模式开始。// 中是模式。

1. 输出包含re单词的
2. 输出第二行包含‘th’，打印第二行

[root@learn200 ~]# cat log.txt 
2 this is a test 
3 Are you like awk 
This's a test 10 
There are orange,apple,mongo
[root@learn200 ~]# awk '/re/' log.txt 
3 Are you like awk 
There are orange,apple,mongo
[root@learn200 ~]# awk '$2 ~ /re/ {print $2}' log.txt 
Are
are
[root@learn200 ~]# 

忽略大小写

[root@learn200 ~]# awk 'BEGIN{IGNORECASE=1} /this/' log.txt 
2 this is a test 
This's a test 10 
[root@learn200 ~]# 

模式取反

[root@learn200 ~]# cat log.txt 
2 this is a test 
3 Are you like awk 
This's a test 10 
There are orange,apple,mongo
[root@learn200 ~]# 
[root@learn200 ~]# awk '$2 !~ /th/' log.txt 
3 Are you like awk 
This's a test 10 
There are orange,apple,mongo
[root@learn200 ~]# 
[root@learn200 ~]# awk '!/th/' log.txt 
3 Are you like awk 
This's a test 10 
There are orange,apple,mongo
[root@learn200 ~]# 

awk脚本

• BEGIN
• END

计算文件大小

[root@learn200 ~]# ls -l *.txt
-rw-r--r--. 1 root root   182 Oct 15  2019 cookies.txt
-rw-r--r--. 1 root root    85 Jun 28 22:32 log.txt
-rw-r--r--. 1 root root 17391 Dec 21  2019 top.txt
[root@learn200 ~]# ls -l *.txt | awk '{sum+=$5} END {print sum}'
17658
[root@learn200 ~]# 
[root@learn200 ~]# ll *.txt | awk 'BEGIN {sum = -1000} {sum+=$5} END{print sum}'
16658