文本处理grep命令

 this is a words file.
 words words to be
  ,    ,  ,   ,  ,  ,  ,  ,   ,  ,
 beginning linux programming 4th edition

 this is a line containing pattern
 ,.<>?;';;;' [] {= = \ \ \| -__!@#$%^&*() !@#$$%%^&*(()*&%@(#$%))

 www.regexper.com
 www.google.com
 www.baidu.com
 www.redhat.com

我们的测试文件名字叫 n，如上所示，共13行。

grep按行检索，按行输出。

1， 搜索特定模式的行

 [lizhen@dhcp-- shell]$ grep words n
 this is a words file.
 words words to be
 [lizhen@dhcp-- shell]$ 

2，单个grep命令可以对多个文件进行检索

[lizhen@dhcp-- shell]$ grep words n n1 n2
n:this is a words file.
n:words words to be
n1:this is a words file.
n1:words words to be
n2:this is a words file.
n2:words words to be
[lizhen@dhcp-- shell]$ 

3，使用正则表达式，添加-E选项，或者直接egrep   (在terminal下可以看到这些被匹配的部分 是被红色 特殊显示的，这里显示的是被匹配到的 行)

[lizhen@dhcp-- shell]$ egrep "[a-o]+" n
this is a words file.
words words to be
beginning linux programming 4th edition
this is a line containing pattern
www.regexper.com
www.google.com
www.baidu.com
www.redhat.com
[lizhen@dhcp-- shell]$ 

4，只输出文件中匹配到的文本部分呢，使用-o

[lizhen@dhcp-- shell]$ grep words n
this is a words file.
words words to be
[lizhen@dhcp-- shell]$ grep words n -o
words
words
words
[lizhen@dhcp-- shell]$ 

5，打印除包含match_pattern行之外的所有行，使用-v

[lizhen@dhcp-- shell]$ grep words n -v
 ,    ,  ,   ,  ,  ,  ,  ,   ,  ,
beginning linux programming 4th edition

this is a line containing pattern
,.<>?;';;;' [] {= = \ \ \| -__!@#$%^&*() !@#$$%%^&*(()*&%@(#$%))

www.regexper.com
www.google.com
www.baidu.com
www.redhat.com
[lizhen@dhcp-- shell]$ 

6，统计文件包含匹配字符串的行数，使用-c   （-c只统计匹配到的行数，并不会统计匹配到的次数）

[lizhen@dhcp-- shell]$ grep words n -c

[lizhen@dhcp-- shell]$ grep words n
this is a words file.
words words to be
[lizhen@dhcp-- shell]$ 

7，统计匹配到的字符串的数量，使用-o    |    wc -l

[lizhen@dhcp-- shell]$ grep -o words n | wc -l

[lizhen@dhcp-- shell]$ grep words n
this is a words file.
words words to be
[lizhen@dhcp-- shell]$ 

8，打印出包含匹配字符串的行号，使用-n

[lizhen@dhcp-128-93 shell]$ grep w -n n n1
n:1:this is a words file.
n:2:words words to be 
n:10:www.regexper.com
n:11:www.google.com
n:12:www.baidu.com
n:13:www.redhat.com
n1:1:this is a words file.
n1:2:words words to be 
n1:10:www.regexper.com
n1:11:www.google.com
n1:12:www.baidu.com
n1:13:www.redhat.com
[lizhen@dhcp-128-93 shell]$

9 打印模式匹配所位于的字符或字节偏移，使用-b  -o

[lizhen@dhcp-- shell]$ grep words n
this is a words file.
words words to be
[lizhen@dhcp-- shell]$ grep words -b -o n
:words
:words
:words
[lizhen@dhcp-- shell]$ 

10，搜索多个文件并找出文本位于哪一个文件中，使用-l

[lizhen@dhcp-- shell]$ grep words n n1
n:this is a words file.
n:words words to be
n1:this is a words file.
n1:words words to be
[lizhen@dhcp-- shell]$ grep words -l n n1
n
n1
[lizhen@dhcp-- shell]$ 

使用-L  大写的L字符，取相反的结果

[lizhen@dhcp-- shell]$ grep words n n1
n:this is a words file.
n:words words to be
n1:this is a words file.
n1:words words to be
[lizhen@dhcp-- shell]$ grep words -l n n1
n
n1
[lizhen@dhcp-- shell]$ grep words -L n n1
[lizhen@dhcp-- shell]$ 

11，递归搜索文件，使用-R -n  （-n选项表示显示所在文件名：行号）

[lizhen@dhcp-- shell]$ grep words . -R -n
./n::this is a words file.
./n::words words to be
./n1::this is a words file.
./n1::words words to be
./n2::this is a words file.
./n2::words words to be
[lizhen@dhcp-- shell]$ 

12，忽略样式中的大小写，使用-i

[lizhen@dhcp-- shell]$ grep WORDS -i n
this is a words file.
words words to be
[lizhen@dhcp-- shell]$ 

13，使用grep匹配多个样式，使用-e

[lizhen@dhcp-128-93 shell]$ grep -e words  -e www -o n
words
words
words
www
www
www
www
[lizhen@dhcp-128-93 shell]$ 

14，使用样式文件，利用grep逐行读取样式文件，grep会将匹配到的行输出

[lizhen@dhcp-- shell]$ grep -f f n
this is a words file.
words words to be
 ,    ,  ,   ,  ,  ,  ,  ,   ,  , 

www.regexper.com
www.google.com
www.baidu.com
www.redhat.com
[lizhen@dhcp-- shell]$ 

15，在grep搜索中指定或排除文件

# grep "main()" . -r --include *.{c,cpp}

#grep "main()" . -r --exclude "readme"

16,grep 的静默输出，使用-q

#########################################################################
# File Name: begin.sh
# Author: lizhen
# mail: lizhen_ok@.com
# Created Time: Wed  May  :: PM CST
#########################################################################
#!/bin/bash
if [ $# -ne   ]
then
    echo "usage: $0 match_text filename"
    exit
fi

match_text=$
filename=$
grep -q "$match_text" $filename

if [ $? -eq  ]
then
    echo "The text exists in the file"
else
    echo "text does not exist in the file"
fi

echo "done!"

[lizhen@dhcp-- shell]$ ./begin.sh words n
The text exists in the file
done!
[lizhen@dhcp-- shell]$ 

17，打印匹配行之前或之后的行，使用-B，-A，-C选项

[lizhen@dhcp-- shell]$ grep www -B  n
this is a line containing pattern
,.<>?;';;;' [] {= = \ \ \| -__!@#$%^&*() !@#$$%%^&*(()*&%@(#$%))

www.regexper.com
www.google.com
www.baidu.com
www.redhat.com
[lizhen@dhcp-- shell]$ grep www -B  n

www.regexper.com
www.google.com
www.baidu.com
www.redhat.com
[lizhen@dhcp-- shell]$ grep www n
www.regexper.com
www.google.com
www.baidu.com
www.redhat.com
[lizhen@dhcp-- shell]$ 

[lizhen@dhcp-- shell]$ grep words -A   n
this is a words file.
words words to be
 ,    ,  ,   ,  ,  ,  ,  ,   ,  ,
[lizhen@dhcp-- shell]$ 

[lizhen@dhcp-- shell]$ grep  n

[lizhen@dhcp-- shell]$ grep  n -C
beginning linux programming 4th edition

[lizhen@dhcp-- shell]$