linux中的awk命令详解

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

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

# 每行按空格或TAB分割（默认情况），输出文本中的1、4项
$ awk '{print $1,$4}' log.txt
---------------------------------------------
2 a
3 like
This's
10 orange,apple,mongo
---------------------------------------------
# 格式化输出
$ awk '{printf "%-8s %-10s\n",$1,$4}' log.txt
---------------------------------------------
2        a
3        like
This's
10       orange,apple,mongo

# log.txt的内容如下：
# 2,this,is,a,test
# 3 Are you like awk
$ awk -F, '{print $1,$2}' log.txt
---------------------------------------------
2 this
3 Are you like awk
# 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
$ awk -F '[ ,]' '{print $1,$2,$5}' log.txt
---------------------------------------------
2 this
3 Are

$ awk -va=1 '{print $1,$1+a}' log.txt
---------------------------------------------
2 3
3 4
This's 1
10 11
$ awk -va=1 '{print $1,$(1+a)}' log.txt
---------------------------------------------
2 this
3 Are
This's a
10 There
$ 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

$ awk '$1>2' log.txt    #命令
#输出
3 Are you like awk
This's a test
10 There are orange,apple,mongo

$ awk '$1==2 {print $1,$3}' log.txt    #命令
#输出
2 is

$ awk '$1>2 && $2=="Are" {print $1,$2,$3}' log.txt    #命令
#输出
3 Are you

# 输出顺序号 NR, 匹配文本行号
$ awk '{print NR,FNR,$1,$2,$3}' log.txt
---------------------------------------------
1 1 2 this is
2 2 3 Are you
3 3 This's a test
4 4 10 There are
# 指定输出分割符
$ awk '{print $1,$2,$5}' OFS=" $ " log.txt
---------------------------------------------
2 $ this $ test
3 $ Are $ awk
This's $ a $
10 $ There $

# 输出第二列包含 "th"，并打印第二列与第四列
$ awk '$2 ~ /th/ {print $2,$4}' log.txt
---------------------------------------------
this a

# 输出包含"re" 的行
$ awk '/re/ ' log.txt
---------------------------------------------
3 Are you like awk
10 There are orange,apple,mongo

$ awk 'BEGIN{IGNORECASE=1} /this/' log.txt
---------------------------------------------
2 this is a test
This's a test

$ awk '$2 !~ /th/ {print $2,$4}' log.txt
---------------------------------------------
Are like
a
There orange,apple,mongo
$ awk '!/th/ {print $2,$4}' log.txt
---------------------------------------------
Are like
a
There orange,apple,mongo

<code>BEGIN{ 这里面放的是执行前的语句 }
END {这里面放的是处理完所有的行后要执行的语句 }
{这里面放的是处理每一行时要执行的语句}</code>

$ 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

$ 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
}

$ 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

$ ls -l *.txt | awk '{sum+=$6} END {print sum}'
--------------------------------------------------
666581

awk 'length>80' log.txt

seq 9 | sed 'H;g' | awk -v RS='' '{for(i=1;i<=NF;i++)printf("%dx%d=%d%s", i, NR, $i, i==NR?"\n":"\t")}'