深入解析Linux 常用命令--awk
-
- 1.概述
- 2.awk命令行格式
- 3.awk示例
- 1）打印所有文件内容
- 2）打印部分列
- 3）模式匹配
- 4）精确匹配
- 5）不匹配
- 6）条件/逻辑组合
- 7）内置变量
- 8）计算
- 9）新增输出内容
- 4.注意事项
1.概述
awk是一个功能十分强大的文本处理命令，本文主要介绍一些常用的文本处理方法。
2.awk命令行格式
格式1： awk ‘{[pattern] action}’ filenames
格式2： awk -F #指定分割字符
格式1：
[root@smart Desktop]# cat test.log
Apr 21 15:34:49 smart user: hello
Apr 21 15:34:59 smart user: hello2
Apr 22 15:45:55 smart test1.bin: test1.c main 15
Apr 22 15:46:08 smart test1.bin: test1.c main 15
[root@smart Desktop]# awk '{print $5}' test.log
user:
user:
test1.bin:
test1.bin:
[root@smart Desktop]#
[root@smart Desktop]# awk '{print}' test.log
Apr 21 15:34:49 smart user: hello
Apr 21 15:34:59 smart user: hello2
Apr 22 15:45:55 smart test1.bin: test1.c main 15
Apr 22 15:46:08 smart test1.bin: test1.c main 15 格式2：
[root@smart Desktop]# awk -F: '{print $1}' test.log
Apr 21 15
Apr 21 15
Apr 22 15
Apr 22 15
[root@smart Desktop]# awk -F: '{print $2}' test.log
34
34
45
46
[root@smart Desktop]# awk -F: '{print $3}' test.log
49 smart user
59 smart user
55 smart test1.bin
08 smart test1.bin
[root@smart Desktop]# 3.awk示例
[root@smart Desktop]# cat table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen1）打印所有文件内容
[root@smart Desktop]# awk '{print}' table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# awk '{print $0}' table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen 2）打印部分列
[root@smart Desktop]# awk '{print $1}' table.txt
Index
1
2
3
[root@smart Desktop]# awk '{print $2}' table.txt
Name
Xiaohong
Xiaoming
Xiaogang3）模式匹配
[root@smart Desktop]# awk '/user/' test.log
Apr 21 15:34:49 smart user: hello
Apr 21 15:34:59 smart user: hello2
[root@smart Desktop]# awk '/1\/3/' table.txt
2 Xiaoming Woman 10 1990/1/3 Shenzhen
[root@smart Desktop]# awk '/1\/3/ {print $2}' table.txt
Xiaoming
[root@smart Desktop]# 4）精确匹配
[root@smart Desktop]# awk '$2=="Xiaoming" {print}' table.txt
2 Xiaoming Woman 10 1990/1/3 Shenzhen5）不匹配
[root@smart Desktop]# awk '/Xiaoming/ {print}' table.txt
2 Xiaoming Woman 10 1990/1/3 Shenzhen
[root@smart Desktop]# awk '!/Xiaoming/ {print}' table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen6）条件/逻辑组合
[root@smart Desktop]# awk '$1>=2 {print}' table.txt
Index Name Sex Age Date Location
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# awk '$1>1 && $1<3 {print}' table.txt
2 Xiaoming Woman 10 1990/1/3 Shenzhen
[root@smart Desktop]# awk '$2=="Xiaoming"||$2=="Xiaohong" {print}' table.txt
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
[root@smart Desktop]# awk '/Xiaoming|Xiaohong/ {print}' table.txt
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
[root@smart Desktop]#
7）内置变量
NR：已读记录数
NF：当前记录域总数
[root@smart Desktop]# awk '{print NF,NR,$0}' table.txt
6 1 Index Name Sex Age Date Location
6 2 1 Xiaohong Man 10 1990/1/2 Shenzhen
6 3 2 Xiaoming Woman 10 1990/1/3 Shenzhen
6 4 3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# awk '{print NF,$0}' table.txt
6 Index Name Sex Age Date Location
6 1 Xiaohong Man 10 1990/1/2 Shenzhen
6 2 Xiaoming Woman 10 1990/1/3 Shenzhen
6 3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# awk '{print NR,$0}' table.txt
1 Index Name Sex Age Date Location
2 1 Xiaohong Man 10 1990/1/2 Shenzhen
3 2 Xiaoming Woman 10 1990/1/3 Shenzhen
4 3 Xiaogang Man 10 1990/1/4 Shenzhen8）计算
[root@smart Desktop]# awk '$4=$4+4 {print $0}' table.txt
Index Name Sex 4 Date Location
1 Xiaohong Man 14 1990/1/2 Shenzhen
2 Xiaoming Woman 14 1990/1/3 Shenzhen
3 Xiaogang Man 14 1990/1/4 Shenzhen
[root@smart Desktop]# awk '{if($4!="Age") $4=$4+4}{ print $0}' table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 14 1990/1/2 Shenzhen
2 Xiaoming Woman 14 1990/1/3 Shenzhen
3 Xiaogang Man 14 1990/1/4 Shenzhen
[root@smart Desktop]#
[root@smart Desktop]# awk '{if($4!="Age") $4=$4+4 print $0}' table.txt
awk: {if($4!="Age") $4=$4+4 print $0}
awk: ^ syntax error
[root@smart Desktop]# awk '{if($4!="Age") $4=$4+4; print $0}' table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 14 1990/1/2 Shenzhen
2 Xiaoming Woman 14 1990/1/3 Shenzhen
3 Xiaogang Man 14 1990/1/4 Shenzhen
[root@smart Desktop]#
9）新增输出内容
[root@smart Desktop]# awk 'BEGIN{print 1 2 3} {print $0}' table.txt
123
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# awk 'BEGIN{print "1 2 3"} {print $0}' table.txt
1 2 3
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# 4.注意事项
1）双引号与单引号
特别注意awk与shell脚本中，单引号与双引号互包含的区别
[root@smart Desktop]# awk "{print}" table.txt
Index Name Sex Age Date Location
1 Xiaohong Man 10 1990/1/2 Shenzhen
2 Xiaoming Woman 10 1990/1/3 Shenzhen
3 Xiaogang Man 10 1990/1/4 Shenzhen
[root@smart Desktop]# awk "$2=="Xiaoming" {print}" table.txt
awk: ==Xiaoming {print}
awk: ^ syntax error
[root@smart Desktop]# awk "$2=='Xiaoming' {print}" table.txt
awk: =='Xiaoming' {print}
awk: ^ syntax error
[root@smart Desktop]#
[root@smart Desktop]# A=1
[root@smart Desktop]# B=2
[root@smart Desktop]# echo "'$A' $B"
'1' 2
[root@smart Desktop]# echo ''$A' $B'
1 $B
[root@smart Desktop]# echo '"$A" $B'
"$A" $B
[root@smart Desktop]#
Juyin@2018/4/28，欢迎留言交流