Linux awk使用

2020-05-19 Linux 阅读量

awk是一种编程语言，用于在linux/unix下对文本和数据进行处理。

awk命令格式和选项

语法形式

awk [options] ‘script’ var=value file(s)
awk [options] -f script_file var=value file(s)

常用命令选项

-F fs: fs指定输入分隔符, fs可以是字符串或正则表达式，如-F:
-v var=value 赋值一个用户定义变量，将外部变量传递给awk
-f script_file 从脚本文件中读取awk命令

基本用法

log.txt文本内容如下：

2 this is a test
3 Are you like awk
This's a test
10 There are orange,apple,mongo

用法一:

1	awk '{[pattern] action}' {filenames} # 行匹配语句 awk ''只能用单引号

实例

# 每行按空格或TAB分割，输出文本中的1、4项
[root@caoxl ~]# awk '{print $1,$4}' log.txt
2 a
3 like
This's 
10 orange,apple,mongo

# 格式化输出
[root@caoxl ~]# awk '{printf "%-8s %-10s\n",$1,$4}' log.txt
2        a         
3        like      
This's             
10       orange,apple,mongo

用法二:

1	awk -F #-F相当于内置变了FS, 指定分割字符

实例

# 使用","分割
[root@caoxl ~]# 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

# 或者使用内建变量
[root@caoxl ~]# awk 'BEGIN{FS=","}{print $1,$2}' log.txt
2 this is a test 
3 Are you like awk 
This's a test 
10 There are orange apple

# 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
2 this
3 Are
This's a
10 There

用法三:

1	awk -v # 设置变量

实例

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

[root@caoxl ~]# 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

用法四:

1	awk -f {awk脚本} {文件名}

实例

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
}

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

运行

[root@caoxl ~]# 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

其他用法:

从文件中找出长度大于30的行

1 2	[root@caoxl ~]# awk 'length>30' log.txt 10 There are orange,apple,mongo

打印九九乘法表

[root@caoxl ~]# seq 9 | sed 'H;g' | awk -v RS='' '{for(i=1;i<=NF;i++)printf("%dx%d=%d%s", i, NR, i*NR, i==NR?"\n":"\t")}'
1x1=1
1x2=2	2x2=4
1x3=3	2x3=6	3x3=9
1x4=4	2x4=8	3x4=12	4x4=16
1x5=5	2x5=10	3x5=15	4x5=20	5x5=25
1x6=6	2x6=12	3x6=18	4x6=24	5x6=30	6x6=36
1x7=7	2x7=14	3x7=21	4x7=28	5x7=35	6x7=42	7x7=49
1x8=8	2x8=16	3x8=24	4x8=32	5x8=40	6x8=48	7x8=56	8x8=64
1x9=9	2x9=18	3x9=27	4x9=36	5x9=45	6x9=54	7x9=63	8x9=72	9x9=81