[求助]grep \W使用疑问

MeRcy_PM

       -i, --ignore-case
              Ignore case distinctions in  both  the  PATTERN  and  the  input
              files.  (-i is specified by POSIX.)
我这有-i，但是貌似把整个正则表达式都忽略大小写了，所以变成了\w吧？

hcc-30:~/mytest/shell> cat bbb
aerrora
<Error>
[ERROR]
:ERROR:


hcc-30:~/mytest/shell> grep -Pi '\Werror\W' bbb
aerrora
herongguang@hcc-30:~/mytest/shell> grep --version
GNU grep 2.5.2

Copyright (C) 1988, 1992-2002, 2004, 2005  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

hcc-30:~/mytest/shell>

hcc-30:~/mytest/shell> grep -Pi '[^a-z]error[^a-z]' bbb<Error>
[ERROR]
:ERROR:

欧阳西风

回复 1# chinasea100


    我在cygwin中测试输出跟你的不太一样

1. 
   
2. $ grep -i "\Werror\W" a.txt
   
3. <Error>
   
4. [ERROR]
   
5. :ERROR:
   
6. 
   

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我的grep版本：

1. 
   
2. $ grep -V
   
3. grep (GNU grep) 2.16
   
4. Copyright (C) 2014 Free Software Foundation, Inc.
   
5. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
   
6. This is free software: you are free to change and redistribute it.
   
7. There is NO WARRANTY, to the extent permitted by law.
   
8. 
   
9. Written by Mike Haertel and others, see <http://git.sv.gnu.org/cgit/grep.git/tree/AUTHORS>.
   
10. 
    

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最后，lz这个问题，我觉着可以不用\W来解决的吧，grep默认是支持单词边界的，可以直接使用单词边界:

1. 
   
2. $ grep -i '\berror\b' a.txt
   
3. <Error>
   
4. [ERROR]
   
5. :ERROR:
   
6. 
   
7. $ grep -i '\<error\>' a.txt
   
8. <Error>
   
9. [ERROR]
   
10. :ERROR:
    
11. 
    

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chinasea100

回复 12# 欧阳西风


    非常感谢,我学习一下边界词怎么用

chinasea100

回复 12# 欧阳西风


    非常感谢你的解答,\b很好用,我也又学了一招