sed和awk学习总结

一些说明

我测试例子都是在mac os x下,freebsd的sed和awk和gnu的都略有不同,甚至osx下得版本都不能使用,我会在注释中说明;

SED基础

常用语法

语法1

sed [options] {sed-commands} {input-file}

# 例子
# -n表示取消默认输出,p表示打印行
$sed -n 'p' /etc/passwd
# 只打印第三行
$sed -n '3p' /etc/passwd
# 打印1，3行
$sed -n '1,3p' /etc/passwd

语法2

sed [options] -f {sed-commands-in-a-file} {input-file}

# 例子
# 打印以root开头或者nobody开头的行
cat sed_example_1.sed
/^root/ p
/^nobody/ p
#
sed -n -f sed_example_1.sed /etc/passwd

语法3

sed [options] -e {sed-command-1} -e {sed-command-2} {input-file}

# 例子
# 打印以root开头或者nobody开头的行
$sed -n -e '/^root/ p' -e '/^nobody/ p' /etc/passwd
#
# 或者
$sed -n \
-e '/^root/ p' \
-e '/^nobody/ p' \
/etc/passwd

语法4

sed [options] '{
sed-command-1
sed-command-2
}' input-file

# 例子
# 打印以root开头或者nobody结尾的行
sed -n '{
/^root/ p
/nobody$/ p
}' /etc/passwd

SED流

• 1 读
• 2. 执行
• 3. 打印
• 4. 重复

源文件

101,Ian Bicking,Mozilla
102,Hakim El Hattab,Whim
103,Paul Irish,Google
104,Addy Osmani,Google
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware

范围

# 在freebsd版sed不能用
$/usr/local/bin/sed -n '1~2 p' source.txt 
101,Ian Bicking,Mozilla
103,Paul Irish,Google
105,Chris Wanstrath,Github
107,Ask Solem Hoel,VMware
#
# 在freebsd版sed不能用
$/usr/local/bin/sed -n '2~3 p' source.txt 
102,Hakim El Hattab,Whim
105,Chris Wanstrath,Github

模式匹配

# 寻找包含Paul的行
$sed -n '/Paul/ p' source.txt
103,Paul Irish,Google
# 从第一行开始到第五行, 从找到开始打印到第五行
$sed -n '/Paul/,5 p' source.txt
103,Paul Irish,Google
104,Addy Osmani,Google
105,Chris Wanstrath,Github
#
# 从匹配Paul行打印达匹配Addy的行
$sed -n '/Paul/,/Addy/ p' source.txt
103,Paul Irish,Google
104,Addy Osmani,Google
# 在freebsd版sed不能用 匹配Paul行再多输出2行
$/usr/local/bin/sed -n '/Paul/,+2 p' source.txt
103,Paul Irish,Google
104,Addy Osmani,Google
105,Chris Wanstrath,Github

删除行

# 删除所有行
$sed 'd' source.txt 
# 只删除第二行
$sed '2 d' source.txt 
...
# 删除第一到第四行
$sed '1,4 d' source.txt
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware
# 删除奇数行
$/usr/local/bin/sed '1~2 d' source.txt
102,Hakim El Hattab,Whim
104,Addy Osmani,Google
106,Mattt Thompson,Heroku
# 删除符合Paul到Addy的行
$sed '/Paul/,/Addy/d' source.txt
101,Ian Bicking,Mozilla
102,Hakim El Hattab,Whim
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware
# 删除空行
$sed '/^$/ d' source.txt
# 删除评论行
$sed '/^#/ d' source.txt

重定向

# 将source.txt内容重定向写到output.txt
$sed 'w output.txt' source.txt
# 和上面一样,但是没有在终端显示
$sed -n 'w output.txt' source.txt
# 只写第二行
$ sed -n '2 w output.txt' source.txt
# 写一到四行到output.txt
$sed -n '1,4 w output.txt'
# 写匹配Ask的行到结尾行到output.txt
$sed -n '/Ask/,$ w output.txt'

替换语法

sed '[address-range|pattern-range] s/original-
string/replacement-string/[substitute-flags]' inputfile

#例子
# 替换Google为Github
$sed 's/Google/Github/' source.txt
101,Ian Bicking,Mozilla
102,Hakim El Hattab,Whim
103,Paul Irish,Github
104,Addy Osmani,Github
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware
# 替换匹配Addy的行里面的Google为Github
$sed '/Addy/s/Google/Github/' source.txt
101,Ian Bicking,Mozilla
102,Hakim El Hattab,Whim
103,Paul Irish,Google
104,Addy Osmani,Github
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware
# 默认s只会替换一行中的第一个匹配项
$sed '1s/a/A/'  source.txt|head -1
101,IAn Bicking,Mozilla
# g可以替换每行的全部符合
$sed '1s/a/A/g'  source.txt|head -1
101,IAn Bicking,MozillA
# 可以直接指定想要替换的第N个匹配项,这里是第二个
$sed '1s/a/A/2'  source.txt|head -1
101,Ian Bicking,MozillA
# 使用w将能够替换的行重定向写到output.txt
$sed -n 's/Mozilla/Github/w output.txt' source.txt
$cat output.txt 
101,Ian Bicking,Github
# 还可以使用i忽略匹配的大小写,看来freebsd的不能用
$/usr/local/bin/sed '1s/ian/IAN/i'  source.txt|head -1
101,IAN Bicking,Mozilla
# 这里有个新的文件
$cat files.txt 
/etc/passwd
/etc/group
# 给每行前和后都添加点字符
$sed 's/\(.*\)/ls -l \1|head -1/' files.txt
ls -l /etc/passwd|head -1
ls -l /etc/group|head -1
# 我要用sed执行这个字符串命令了 无奈..mac上得sed都不行
dongwm@bj-1:~$ sed 's/^/ls -l /e' files.txt
-rw-r--r-- 1 root root 1627 Oct 14 14:30 /etc/passwd
-rw-r--r-- 1 root root 807 Oct 14 14:30 /etc/group
# sed分隔符不只可以使用'/'
$sed 's|/usr/local/bin|/usr/bin|' path.txt
$sed 's^/usr/local/bin^/usr/bin^' path.txt
$sed 's@/usr/local/bin@/usr/bin@' path.txt
$sed 's!/usr/local/bin!/usr/bin!' path.txt

替换覆盖

sed '{
s/Google/Github/
s/Git/git/ 
}' source.txt 

101,Ian Bicking,Mozilla
102,Hakim El Hattab,Whim
103,Paul Irish,github
104,Addy Osmani,github
105,Chris Wanstrath,github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware

神奇的&

$sed 's/^[0-9][0-9][0-9]/[&]/g'
[101],Ian Bicking,Mozilla
[102],Hakim El Hattab,Whim
[103],Paul Irish,Google
[104],Addy Osmani,Google
[105],Chris Wanstrath,Github
[106],Mattt Thompson,Heroku
[107],Ask Solem Hoel,VMware
#
$sed 's/^.*/<\&>/' source.txt 
<101,Ian Bicking,Mozilla>
<102,Hakim El Hattab,Whim>
<103,Paul Irish,Google>
<104,Addy Osmani,Google>
<105,Chris Wanstrath,Github>
<106,Mattt Thompson,Heroku>
<107,Ask Solem Hoel,VMware>

正则

# ^表示匹配以什么开头
$sed -n '/^101/ p' source.txt      
101,Ian Bicking,Mozilla
# $表示匹配以什么结尾
$sed -n '/Github$/ p' source.txt 
105,Chris Wanstrath,Github
# .表示单个字符,下面的匹配一个逗号然后I然后2个单字符
$sed -n '/,I../ p' source.txt
101,Ian Bicking,Mozilla
# *表示匹配0个或者多个, \+表示匹配一个或者多个, \?表示匹配0个或者1个
# [0-9]表示匹配数字,下面匹配包含3或者4的行
$sed -n '/[34]/ p ' source.txt      
103,Paul Irish,Google
104,Addy Osmani,Google
# -表示范围,这里匹配3,4,5
$sed -n '/[3-5]/ p ' source.txt
103,Paul Irish,Google
104,Addy Osmani,Google
105,Chris Wanstrath,Github
# |表示或者的关系
$/usr/local/bin/sed -n '/102\|103/ p ' source.txt
102,Hakim El Hattab,Whim
103,Paul Irish,Google
# 看一个文件
$cat numbers.txt 
123
1234
12345
123456
# {m} 表示前面的匹配的重复次数
$sed -n '/^[0-9]\{5\}$/ p' numbers.txt
12345
#{m,n } 表示匹配m-n的次数都算
sed -n '/^[0-9]\{3,5\}$/ p' numbers.txt
123
1234
12345
# 删除所有注释行和空行
$sed -e 's/#.*//' -e '/^$/ d' /etc/profile                          
# 转化windows文件到unix格式
$sed 's/.$//' filename                              
#                           
#\1表示第一个正则匹配到的数据
$sed 's/\([^,]*\).*/\1/g' source.txt |head -1
101
#给每个单词第一个字母加括号
$echo "Dong Wei Ming" | /usr/local/bin/sed 's/\(\b[A-Z]\)/\(\1\)/g'
(D)ong (W)ei (M)ing
$/usr/local/bin/sed 's/\(^\|[^0-9.]\)\([0-9]\+\)\([0-9]\{3\}\)/\1\2,\3/g' numbers.txt
123
1,234
12,345
123,456
# 只取第一和第三列,并且换了他们的位置
$sed 's/\([^,]*\),\([^,]*\),\([^,]*\).*/\3,\1/g' source.txt
Mozilla,101
Whim,102
Google,103
Google,104
Github,105
Heroku,106
VMware,107


GNU SED


# \l能将后面的一个字符变成小写
$sed 's/Ian/IAN/' source.txt|head -1               
101,IAN Bicking,Mozilla
$/usr/local/bin/sed 's/Ian/IA\lN/' source.txt|head -1 
101,IAn Bicking,Mozilla
# \L能将后面的字符都变成小写
$/usr/local/bin/sed 's/Ian/I\LAN/' source.txt|head -1
101,Ian Bicking,Mozilla
# \u能将后面的一个字符变成大写
$/usr/local/bin/sed 's/Ian/IA\un/' source.txt|head -1
101,IAN Bicking,Mozilla
# \U能将后面的字都变成大写
$/usr/local/bin/sed 's/Ian/\Uian/' source.txt|head -1 
101,IAN Bicking,Mozilla
# \E能打断\L或者\U改变大小写
$/usr/local/bin/sed 's/Ian/\Uia\En/' source.txt|head -1
101,IAn Bicking,Mozilla
# 使用以上功能:调换前2列,把名字列全部大写,公司列全部小写
$/usr/local/bin/sed 's/\([^,]*\),\([^,]*\),\(.*\).*/\U\2\E,\1,\L\3/g' source.txt
IAN BICKING,101,mozilla
HAKIM EL HATTAB,102,whim
PAUL IRISH,103,google
ADDY OSMANI,104,google
CHRIS WANSTRATH,105,github
MATTT THOMPSON,106,heroku
ASK SOLEM HOEL,107,vmware

sed使用示例

SED可执行脚本

$cat testscript.sed
#!/usr/bin/sed -nf
/root/ p
/nobody/ p
$chmod u+x testscript.sed
$./testscript.sed /etc/passwd 
nobody:*:-2:-2:Unprivileged User:/var/empty:/usr/bin/false
root:*:0:0:System Administrator:/var/root:/bin/sh
daemon:*:1:1:System Services:/var/root:/usr/bin/false
_cvmsroot:*:212:212:CVMS Root:/var/empty:/usr/bin/false

SED修改源文件和备份

#-i会修改源文件,但是可以同时使用bak备份
$sed -ibak 's/Ian/IAN/' source.txt 
# or
sed --in-place=bak 's/Ian/IAN/' source.txt 
# 这样会存在一个文件source.txtbak

行后增加语法

sed '[address] a the-line-to-append' input-file

#例子
$/usr/local/bin/sed '2 a 108,Donald Stufft, Nebula' source.txt
101,IAN Bicking,Mozilla
102,Hakim El Hattab,Whim
108,Donald Stufft, Nebula
103,Paul Irish,Google
104,Addy Osmani,Google
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware

行前插入语法

sed '[address] i the-line-to-insert' input-file

#例子
$/usr/local/bin/sed '2 i 108,Donald Stufft, Nebula' source.txt
101,IAN Bicking,Mozilla
108,Donald Stufft, Nebula
102,Hakim El Hattab,Whim
103,Paul Irish,Google
104,Addy Osmani,Google
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware

修改行语法

sed '[address] c the-line-to-insert' input-file

#例子
# 修改符合Paul行为...
$/usr/local/bin/sed '/Paul/ c 108,Donald Stufft, Nebula' source.txt
101,IAN Bicking,Mozilla
102,Hakim El Hattab,Whim
108,Donald Stufft, Nebula
104,Addy Osmani,Google
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware

SED其他

# -l会显示隐藏字符比如'\t', = 可以显示行号
$sed -l = source.txt
# y或翻译你要转换的字符,这里I会转化成i，B转换成b
$sed 'y/IB/ib/' source.txt |head -1
101,iAN bicking,Mozilla

sed练习

    1.把123变成[123](不要sed “s/([0-9]{3})/[\1]/“)
    2.这是什么意思: echo “1\n2\n3\n4”|sed -n “/2/, +2p”(gnu sed)
    3.这是什么意思: echo “1\n2\n3”|sed ‘2 c 4’ (gnu sed)
    4.把This is UPPER变成IS,This,upper(gnu sed)
    5.这是什么意思: sed ‘H;x;s/^(.)\n(.)/\2\1/‘
    6.实现tac命令的功能

SED高级话题(保持空间和模式空间)

源码

#先看一个文件
$cat source2.txt 
Ian Bicking
Mozilla
Hakim El Hattab
Whim
Paul Irish
Google
Chris Wanstrath
Github
Mattt Thompson
Heroku

交换模式空间

# 通过公司找到这个人, x命令交换当前行到保持空间,
# n读取下一行到模式空间; 匹配这个模式空间, 假如符合,再交换模式空间，打印
$/usr/local/bin/sed  -n -e 'x;n' -e '/Whim/{x;p}' source2.txt  
Hakim El Hattab

拷贝模式空间到保持空间

# 还是前面的需求.h拷贝模式空间到保持空间, 
# 如果当前模式空间不匹配, 就拷贝空间到保持空间. 他们会一样
# 但是当Whim匹配保持空间还是上面一行关于名字的缓存
$/usr/local/bin/sed  -n -e '/Whim/!h' -e '/Whim/{x;p}' source2.txt  
Hakim El Hattab

增加模式空间到保持空间

# 当我根据Whim想显示他的名字和公司名字呢？ - 给保持空间多加一个
# H表示增加模式空间到保持空间
$/usr/local/bin/sed -n -e '/Whim/!h' -e '/Whim/{H;x;p}' source2.txt 
Hakim El Hattab
Whim
# 显示的好看一点
$/usr/local/bin/sed -n -e '/Whim/!h' -e '/Whim/{H;x;s/\n/:/;p}' source2.txt 
Hakim El Hattab:Whim

拷贝保持空间到模式空间

# 还是前面的需求.g拷贝保持空间到模式空间
$/usr/local/bin/sed  -n -e '/Whim/!h' -e '/Whim/{g;p}' source2.txt   
Hakim El Hattab

增加保持空间到模式空间


# 前面的前面, 输出是Hakim El Hattab:Whim 怎么样翻转呢？
# G就是反向的
$/usr/local/bin/sed -n -e '/Whim/!h' -e '/Whim/{G;s/\n/:/;p}' source2.txt  
Whim:Hakim El Hattab

增加下一行到模式空间

$/usr/local/bin/sed -e '{N;s/\n/:/}' source2.txt
Ian Bicking:Mozilla
Hakim El Hattab:Whim
Paul Irish:Google
Chris Wanstrath:Github
Mattt Thompson:Heroku


LABEL

# 给匹配Github的行,在使用名字:公司的前面加一个*, 
#只有匹配Github的模式空间和保持空间才会执行s/^/*/
$cat label.sed 
#!/usr/local/bin/sed -nf
h;n;H;x
s/\n/:/
/Github/!b end
s/^/*/
:end p
$chmod u+x label.sed
./label.sed source2.txt
Ian Bicking:Mozilla
Hakim El Hattab:Whim
Paul Irish:Google
*Chris Wanstrath:Github
Mattt Thompson:Heroku


    

#例子
# 把mac地址的冒号替换掉
"130531170341903612","259594",2013-05-31T09:04:25Z,"1c:b0:94:b2:85:bd"
#                       
1. sed "s/\([0-9a-zA-Z]\{2\}\):\([0-9a-zA-Z]\{2\}\):\([0-9a-zA-Z]\{2\}\):\([0-9a-zA-Z]\{2\}\):\([0-9a-zA-Z]\{2\}\):\([0-9a-zA-Z]\{2\}\)/\1\2\3\4\5\6/"
2. sed "s/\(.*\):\(.*\):\(.*\):\(.*\):\(.*\):\(.*\)/\1\2\3\4\5\6/"
3. sed -e "s/T\(.*\):\(.*\):\(.*\)Z/\1#\2#\3/" -e "s/://g" -e "s/#/:/g"

AWK

AWK基本语法

#语法1
awk -Fs '/pattern/ {action}' input-file
#or
awk -Fs '{action}' intput-file
# -F表示设置分隔符,不指定就是默认为空字符

#例子
# 用:分割，查找匹配mail的行并且打印冒号分割后的第一部分
awk -F: '/mail/ {print $1}' /etc/passwd
_mailman
_clamav
_amavisd

AWK数据结构

# 1 BEGIN { awk-commands } 在执行awk body之前执行这个awk-commands,而且只一次
# 2 /pattern/ {action} body部分，也就是awk要执行的主体,比如十行,那么这个主体就调用10次
# 3 END { awk-commands } 在执行完body之后执行,也是只一次
$awk 'BEGIN { FS=":";print "---header---" } /mail/ {print $1} \
END { print "---footer---"}' /etc/passwd
---header---
_mailman
_clamav
_amavisd
---footer---
# 当然可以只有其中一种或者集中数据结构
awk -F: 'BEGIN { print "UID"} { print $3 }' /etc/passwd |\
sed -e '/^$/ d'|head -2
UID
-2
$ awk 'BEGIN { print "Hello World!" }'
Hello World!

源码2

# 这是一个文件,分别是id, 描述, 价钱和库存
$cat items.txt 
101,HD Camcorder,Video,210,10
102,Refrigerator,Appliance,850,2
103,MP3 Player,Audio,270,15
104,Tennis Racket,Sports,190,20
105,Laser Printer,Office,475,5

源码3

# 这是一个销售数据,分别是id和1-6月的销售情况
$cat items-sold.txt
101 2 10 5 8 10 12
102 0 1 4 3 0 2
103 10 6 11 20 5 13
104 2 3 4 0 6 5
105 10 2 5 7 12 6

PRINT


    

# 默认print就是打印文件全文到终端
$awk '{print}' source.txt
# 下面是通过,分割,输出第二段。$0表示全行,类似shell用法
$awk -F ',' '{print $2}' source.txt
Ian Bicking
Hakim El Hattab
Paul Irish
Addy Osmani
Chris Wanstrath
Mattt Thompson
Ask Solem Hoel
# or
$awk -F "," '{print $2}' source.txt
$awk -F, '{print $2}' source.txt
# 一个格式化更好看些的效果
awk -F ',' 'BEGIN \                         
{ print "-------------\nName\tComp\n-------------"} \
{ print $2,"\t",$3;} \  
END { print "-------------"; }' source.txt 
-------------
Name    Comp
-------------
Ian Bicking      Mozilla
Hakim El Hattab      Whim
Paul Irish   Google
Addy Osmani      Google
Chris Wanstrath      Github
Mattt Thompson   Heroku
Ask Solem Hoel   VMware
-------------

模式匹配

# 用逗号做分隔符, 打印第二和第三列
$awk -F ',' '/Whim/ {print $2, $3}' source.txt
Hakim El Hattab Whim
# 可以加点格式化语句
$awk -F ',' '/Whim/ {print "Whim\"s name:", $2}' source.txt
Whim"s name: Hakim El Hattab

AWK内置变量 - FS

$awk -F ',' '{print $2, $3}' source.txt  
Ian Bicking Mozilla
Hakim El Hattab Whim
Paul Irish Google
Addy Osmani Google
Chris Wanstrath Github
Mattt Thompson Heroku
Ask Solem Hoel VMware
# 可以使用内置的FS - 输入字段分隔符 实现相同的功能
$awk 'BEGIN {FS=","} {print $2, $3}' source.txt
# 先看一个文件
$cat source-multiple-fs.txt 
101,Ian Bicking:Mozilla%
102,Hakim El Hattab:Whim%
103,Paul Irish:Google%
104,Addy Osmani:Google%
105,Chris Wanstrath:Github%
106,Mattt Thompson:Heroku%
107,Ask Solem Hoel:VMware%
# 发现上面的分隔符有三种:逗号分号和百分号,这样就可以这样使用
# awk 'BEGIN {FS="[,:%]"} {print $2, $3}' source-multiple-fs.txt

AWK内置变量 - OFS

$awk -F ',' '{print $2, ":", $3}' source.txt 
Ian Bicking : Mozilla
Hakim El Hattab : Whim
Paul Irish : Google
Addy Osmani : Google
Chris Wanstrath : Github
Mattt Thompson : Heroku
Ask Solem Hoel : VMware
# 其实可以用内置的OFS - 输出字段分隔符
$awk -F ',' 'BEGIN { OFS=":" } { print $2, $3 }' source.txt

AWK内置变量 - RS

$cat source-one-line.txt 
1,one:2,two:3,three:4,four
# 现在我想分割成(1，one),(2, two)这样的效果
$awk -F, '{print $2}' source-one-line.txt 
one:2
# 这个没有实现我想要的效果
# 使用RS - 记录分隔符, 他能帮你把单行内容先分割然后再按-F分割
$awk -F, 'BEGIN { RS=":" } { print $2 }' source-one-line.txt
one
two
three
four

AWK内置变量 - ORS

# RS是输入, ORS就是输出
$awk 'BEGIN { FS=","; OFS="\n";ORS="\n---\n" } \
{print $1,$2,$3}' source.txt|head -8
101
Ian Bicking
Mozilla
---
102
Hakim El Hattab
Whim
---

AWK内置变量 - NR

# NR是记录的数目
$awk 'BEGIN {FS=","} \
{print "Emp Id of record number",NR,"is",$1;} \
END {print "Total number of records:",NR}' source.txt
Emp Id of record number 1 is 101
Emp Id of record number 2 is 102
Emp Id of record number 3 is 103
Emp Id of record number 4 is 104
Emp Id of record number 5 is 105
Emp Id of record number 6 is 106
Emp Id of record number 7 is 107
Total number of records: 7

AWK内置变量 - FILENAME,FNR

# FILENAME显示了当前文件, FNR关联到当前文件的记录数
awk 'BEGIN {FS=","} \
{print FILENAME ": record number",FNR,"is",$1;} \
END {print "Total number of records:",NR}' \
source.txt source-multiple-fs.txt
source.txt: record number 1 is 101
source.txt: record number 2 is 102
source.txt: record number 3 is 103
source.txt: record number 4 is 104
source.txt: record number 5 is 105
source.txt: record number 6 is 106
source.txt: record number 7 is 107
source-multiple-fs.txt: record number 1 is 101
source-multiple-fs.txt: record number 2 is 102
source-multiple-fs.txt: record number 3 is 103
source-multiple-fs.txt: record number 4 is 104
source-multiple-fs.txt: record number 5 is 105
source-multiple-fs.txt: record number 6 is 106
source-multiple-fs.txt: record number 7 is 107
Total number of records: 14

AWK变量

# 变量支持数字,字符和下划线
# 这个文件多加了一列star数, 现在我想统计整个文件的star
$cat source-star.txt
101,Ian Bicking,Mozilla,1204
102,Hakim El Hattab,Whim,4029
103,Paul Irish,Google,7200
104,Addy Osmani,Google,2201
105,Chris Wanstrath,Github,1002
106,Mattt Thompson,Heroku,890
107,Ask Solem Hoel,VMware,2109
# 使用awk的变量,在begin的时候声明total,在body体里面
# 累加total值，在end里面打印
$cat total-star.awk 
BEGIN {
    FS=",";
    total=0; }
{
 print $2 "'s star is: " $4;
 total=total+$4
} END {
    print "---\nTotal star = *"total;
}
awk -f total-star.awk source-star.txt
Ian Bicking's star is: 1204
Hakim El Hattab's star is: 4029
Paul Irish's star is: 7200
Addy Osmani's star is: 2201
Chris Wanstrath's star is: 1002
Mattt Thompson's star is: 890
Ask Solem Hoel's star is: 2109
---
Total star = *18635

自增长/减少

# 可以使用++或者--,但是注意前后
$awk -F, '{print --$4}' source-star.txt
1203
4028
7199
2200
1001
889
2108
$awk -F, '{print $4--}' source-star.txt 
# 咦 竟然没有变
1204
4029
7200
2201
1002
890
2109
# 想达到--$4的目的就得这样
$awk -F ',' '{$4--; print $4}' source-star.txt
1203
4028
7199
2200
1001
889
2108

字符串操作

$cat string.awk
BEGIN {
    FS=",";
    OFS=",";
    string1="GO";
    string2="OGLE";
    numberstring="100";
    string3=string1 string2;
    print "Concatenate string is:" string3;
    numberstring=numberstring+1;
    print "String to number:" numberstring;
}
# 字符串会直接相连, 字符串相加会自动转化成数字相加
$awk -f string.awk 
Concatenate string is:GOOGLE
String to number:101

复合运算

$cat assignment.awk
BEGIN {
 FS=",";
 OFS=",";
 total1 = total2 = total3 = total4 = total5 = 10;
 total1 += 5; print total1;
 total2 -= 5; print total2;
 total3 *= 5; print total3;
 total4 /= 5; print total4;
 total5 %= 5; print total5;
}
$awk -f assignment.awk

比较操作

# 只会显示小于1005的行
$awk -F "," '$4 <= 1005' source-star.txt
105,Chris Wanstrath,Github,1002
106,Mattt Thompson,Heroku,890
$awk -F "," '$1 == 103 {print $2}' source-star.txt 
Paul Irish
# 你也可以加多个条件 这里||表示或者  && 表示和
$awk -F "," '$4 > 3000 || $4 <= 880 {print $2}' source-star.txt
Hakim El Hattab
Paul Irish

正则

# ~ 表示匹配, ！~ 表示不匹配
$awk -F "," '$3 ~ "Github"' source.txt
105,Chris Wanstrath,Github
$awk -F "," '$3 !~ "Google"' source.txt
101,Ian Bicking,Mozilla
102,Hakim El Hattab,Whim
105,Chris Wanstrath,Github
106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware
# NF是分割项数目, $NF表示最后一个分割项, 这里是找最后一个分割项是/bin/sh的就会累加n
$awk -F ':' '$NF ~ /\/bin\/sh/ { n++ }; END { print n \
}' /etc/passwd

IF语法

if (conditional-expression)
    action
    
if (conditional-expression)
{
    action1;
    action2; 
}

#例子
# 和上面的一个例子一样
$awk -F "," '{ if ($3 ~ "Github") print $0}' source.txt
105,Chris Wanstrath,Github

IF ELSE语法

if (conditional-expression)
    action1
else
    action2
# or
conditional-expression ? action1 : action2 ;


#例子
# 打印单行因为%2,奇数取余
$awk 'ORS=NR%2?",":"\n"' source.txt                    
101,Ian Bicking,Mozilla,102,Hakim El Hattab,Whim
103,Paul Irish,Google,104,Addy Osmani,Google
105,Chris Wanstrath,Github,106,Mattt Thompson,Heroku
107,Ask Solem Hoel,VMware,

WHILE语法

while(condition)
actions

#例子
# 把第二列和其之后的每列加起来
$cat while.awk 
{
    i=2; total=0;
    while (i <= NF) {
        total = total + $i;
        i++;
 }
    print "Item", $1, ":", total, "quantities sold";
}
$awk -f while.awk items-sold.txt
Item 101 : 47 quantities sold
Item 102 : 10 quantities sold
Item 103 : 65 quantities sold
Item 104 : 20 quantities sold
Item 105 : 42 quantities sold

### DO WHILE语法

do while至少会执行一次

do
action
while(condition)

#例子
# 用do-while方法实现上一次的例子
$cat dowhile.awk 
{
    i=2; total=0;
 do
 {
     total = total + $i;
     i++;
 } while (i <= NF)
 print "Item", $1, ":", total, "quantities sold";
}
$awk -f dowhile.awk items-sold.txt
Item 101 : 47 quantities sold
Item 102 : 10 quantities sold
Item 103 : 65 quantities sold
Item 104 : 20 quantities sold
Item 105 : 42 quantities sold

FOR语法

for(initialization;condition;increment/decrement)
actions

#例子
$echo "1 2 3 4" | awk '{ for (i = 1; i <= NF; i++) total = total+$i }; \
END { print total }'  

# 再来个for版本的例子
$cat for.awk 
{
    total=0;
    for (i=2; i <= NF; i++)
        total = total + $i;
    print "Item", $1, ":", total, "quantities sold";
}
$awk -f for.awk items-sold.txt
Item 101 : 47 quantities sold
Item 102 : 10 quantities sold
Item 103 : 65 quantities sold
Item 104 : 20 quantities sold
Item 105 : 42 quantities sold

BREAK,CONTINUE,EXIT

# 程序一直运行打印Iteration,并且累加x,直到x等于10停止程序-break
$ awk 'BEGIN{
x=1;
while(1)
{
print "Iteration";
if ( x==10 )
break;
x++;
}}'
# x从1到10, 如果x等于5 直接直接累加x而不打印
$awk 'BEGIN{
x=1;
while(x<=10)
{
if(x==5){
x++;
continue;
}
print "Value of x",x;x++;
}
}'
# x从1到10,当x等于5的时候程序直接退出
$awk 'BEGIN{
x=1;
while(x<=10)
{
if(x==5){
exit;}
print "Value of x",x;x++;
}
}'

关联数组

# awk 的关联数组中item[101]和item["101"]意义一样
$awk 'BEGIN { item[101]="Github"; print item["101"]}' 
Github
# 可以用in检验是否包含本项
$awk 'BEGIN { item[101]="a"; if ( 101 in item ) print "Has 101"}'
Has 101
# 还可以使用for循环读取列表
$cat array-for-loop.awk
BEGIN {
    item[101]="Github";
    item[21]="Google";
    for (x in item)
        print item[x];
}
$awk -f array-for-loop.awk
Github
Google
# 多维数组, delete可以删除元素.PS item[2,1]这样的格式有问题
# 因为会被翻译成2#2("2\0342"),假设要设置分隔符可以使用SUBSEP=",";
$awk 'BEGIN { item["1,1"]="Github"; item["1,2"]="Google"; \
item["2,1"]="Whim"; delete item["2,1"];
for (x in item)
print "Index",x,"contains",item[x];}'
Index 1,1 contains Github
Index 1,2 contains Google

数组排序

# 这里需要gnu awk了 使用了asort排序
$cat asort.awk 
BEGIN {
 item[101]="Github";
 item[22]="Whim";
 item[50]="Google";
 print "------Before asort------"
 for (x in item)
     print "Index",x,"contains",item[x];
 total = asort(item);
 print "------After asort------"
 for (x in item)
     print "Index",x,"contains",item[x];
}
#
$gawk -f asort.awk
------Before asort------
Index 22 contains Whim
Index 50 contains Google
Index 101 contains Github
------After asort------
Index 1 contains Github
Index 2 contains Google
Index 3 contains Whim
# 大家请注意上面的例子,排序后已经忘记了原来item的index位置
# 而asorti可以帮助你记录这个位置
$cat asorti.awk
BEGIN {
 item[101]="Github";
 item[22]="Whim";
 item[50]="Google";
 print "----- Function: asort -----"
 total = asort(item,itemdesc);
 for (i=1; i<= total; i++)
    print "Index",i,"contains",itemdesc[i];
 print "----- Function: asorti -----"
 total = asorti(item,itemabbr);
 for (i=1; i<= total; i++)
     print "Index",i,"contains",itemabbr[i];
}
$gawk -f asorti.awk
----- Function: asort -----
Index 1 contains Github
Index 2 contains Google
Index 3 contains Whim
----- Function: asorti -----
Index 1 contains 101
Index 2 contains 22
Index 3 contains 50

格式化打印

# \n是换行
$awk 'BEGIN { printf "Line 1\nLine 2\n" }'
Line 1
Line 2
# \t是tab
$awk 'BEGIN \
{ printf "Field 1\t\tField 2\tField 3\tField 4\n" }'
Field 1     Field 2 Field 3 Field 4
# \v是垂直tab
$awk 'BEGIN \
{ printf "Field 1\vField 2\vField 3\vField 4\n" }'
Field 1
    Field 2
       Field 3
      Field 4
# %s字符串; %c单个字符; %d数字; %f浮点数......
$cat printf-width.awk 
BEGIN {
FS=","
printf "%3s\t%10s\t%10s\t%5s\t%3s\n",
    "Num","Description","Type","Price","Qty"
printf "-----------------------------------------------------\n"
}
{
    printf "%3d\t%10s\t%10s\t%g\t%d\n", $1,$2,$3,$4,$5
}
awk -f printf-width.awk items.txt 
Num Description       Type  Price   Qty
-----------------------------------------------------
101 HD Camcorder         Video  210 10
102 Refrigerator     Appliance  850 2
103 MP3 Player       Audio  270 15
104 Tennis Racket       Sports  190 20
105 Laser Printer       Office  475 5

内置函数

# int - 将数字转换成整形, 类似的函数还有sqrt, sin, cos...
$awk 'BEGIN {print int(4.1);print int(-6.22);print int(strings)}'
-6
# rand - 随机0-1的数字; srand -初始化随机数的初始值
$cat srand.awk 
BEGIN {
    srand(5);
    count=0;
    max=30;
    while (count < 5) {
        # 随机数范围为5-30
        rnd = int(rand() * max);
        print rnd;
        count++;
    }
}
# 使用osx的awk随机范围不对
$gawk -f srand.awk
# index - 所查字符在字符串中的位置,没找到会返回0
awk 'BEGIN{str="This is a test"; print index(str, "a"); print index(str, "y")}'
# length - 字符串的长度
$awk -F, '{print length($0)}' source.txt
# split - 分片 PS:使用awk分片的顺序有问题;
# split第一个参数是要分割的内容,第二个是分割后的结果保存的数组,第三个是使用的分隔符
$echo "101 arg1:arg2:arg3"|gawk '{split($2,out,":"); for (x in out) print out[x];}'
arg1
arg2
arg3
# substr - 取字符串范围内容;
# 第一个参数是要取的内容, 第二个是开始位置(从1开始),第三个是要取的长度
$echo "This is test"|awk '{print substr($3,2,2);}'
es
# sub - 替换原来的字符串,但是只替换第一个符合项; gsub - 替换全部选择项
$awk 'BEGIN{str="ThIs is test"; sub("[Ii]s","e", str); print str;}'
The is test
$awk 'BEGIN{str="ThIs is test"; gsub("[Ii]s","e", str); print str;}'
The e test
# match - 返回某子字符串是否匹配了某字符串;
# RSTART - awk 自带变量返回匹配的开始位置
# RLENGTH - awk 自带变量返回匹配串的长度
$awk 'BEGIN{str="This is test"; if (match(str, "test")) {print substr(str,RSTART,RLENGTH)}}'  
# tolower/toupper - 把字符串都变成小写/大写
$awk 'BEGIN{str="This is test"; print tolower(str); print toupper(str);}'
this is test
THIS IS TEST
# ARGC - 参数的数量; ARGV参数的数组
$cat arguments.awk
BEGIN {
    print "ARGC=",ARGC
    for (i = 0; i < ARGC; i++)
  print ARGV[i]
}

内置变量

# ENVIRON - 系统环境变量
$cat environ.awk
BEGIN {
 OFS="="
 for(x in ENVIRON)
     print x,ENVIRON[x];
}
# IGNORECASE - 设置为1 忽略大小写
$gawk 'BEGIN{IGNORECASE=1} /github/{print}' source.txt
105,Chris Wanstrath,Github

位运算

$cat bits.awk
BEGIN {
 number1=15
 number2=25
 print "AND: " and(number1,number2);
 print "OR: " or(number1,number2)
 print "XOR: " xor(number1,number2)
 print "LSHIFT: " lshift(number1,2)
 print "RSHIFT: " rshift(number1,2)
}
$gawk -f bits.awk
AND: 9
OR: 31
XOR: 22
LSHIFT: 60
RSHIFT: 3

自定义函数语法

function fn-name(parameters)
{
 function-body
}

#例子
# 函数的位置不重要
$cat function-debug.awk 
function mydebug (message) {
    print ("Debug Time:" strftime("%a %b %d %H:%M:%S %Z %Y", systime()))
    print (message)
}
{
    mydebug($NF)
}
$gawk -f function-debug.awk source.txt
Debug Time:Wed Dec 11 22:14:43 CST 2013
Bicking,Mozilla
Debug Time:Wed Dec 11 22:14:43 CST 2013
Hattab,Whim
Debug Time:Wed Dec 11 22:14:43 CST 2013
Irish,Google
Debug Time:Wed Dec 11 22:14:43 CST 2013
Osmani,Google
Debug Time:Wed Dec 11 22:14:43 CST 2013
Wanstrath,Github
Debug Time:Wed Dec 11 22:14:43 CST 2013
Thompson,Heroku
Debug Time:Wed Dec 11 22:14:43 CST 2013
Hoel,VMware

系统调用

# 使用system函数可以调用shell命令
$awk 'BEGIN { system("date") }'
Wed Dec 11 22:24:27 CST 2013
# systime 和 strftime上面见过了.处理时间和格式化时间
$gawk 'BEGIN { print strftime("%c",systime()) }'
Wed Dec 11 22:25:32 2013

学完本章的练习

    1.获取来连接mongodb的各服务器产生的连接数
    2.获取nginx日志ip访问数在一个小时里面,从多到少的总次数排行(排行用到了sort)
    3.打印question_awk3.txt包含Addy和Mattt之间的行
    4.不使用sort过滤重复行
    5.将2个文件合并成一行,但username不一定在2个文件同一行
    6.输出2个文件1中有,2中没有的行
    7.这是什么意思: gawk -vcmd=’ls -l’ ‘BEGIN{while ( (cmd | getline var) > 0) {print var} close(cmd)}’

AWK高级话题

GETLINE

# awk首先读入一行，接着处理getline函数再获得一行....下面显示的就是奇数行
$awk -F"," '{print $0;getline;}' source.txt 
101,Ian Bicking,Mozilla
103,Paul Irish,Google
105,Chris Wanstrath,Github
107,Ask Solem Hoel,VMware
# 我们使用getline 并把这行变量赋值给tmp
$awk -F, '{getline tmp; print "$0->", $0; print "tmp->", tmp;}' source.txt
$0-> 101,Ian Bicking,Mozilla
tmp-> 102,Hakim El Hattab,Whim
$0-> 103,Paul Irish,Google
tmp-> 104,Addy Osmani,Google
$0-> 105,Chris Wanstrath,Github
tmp-> 106,Mattt Thompson,Heroku
$0-> 107,Ask Solem Hoel,VMware
tmp-> 106,Mattt Thompson,Heroku
# 执行外部程序, close可关闭管道,比如这里必须是`|getline`之前的命令
$awk 'BEGIN{"date"| getline;close("date");print "Timestamp:" $0}'
Timestamp:Wed Dec 11 22:41:52 CST 2013
# or
$awk 'BEGIN{"date"| getline timestamp;close("date");print "Timestamp:" timestamp}'
Timestamp:Wed Dec 11 22:44:08 CST 2013

原文链接