Grep与正则表达式

其实学过正则表达式之后这些就不算啥事儿了,建议先学一下正则然后再来看.

不过直接看下面的更功利一些,毕竟看完了就可以直接用了.

下面这个是测试文的内容:

  1. ➤ cat -n fortune
  2.     1    All generalizations are false, including this one.
  3.     2            -- Mark Twain
  4.     3    Many pages make a thick book, except for pocket Bibles which are on very
  5.     4    very thin paper.
  6.     5    
  7.     6    Remark of Dr. Baldwin's concerning upstarts: We don't care to eat toadstools
  8.     7    that think they are truffles.
  9.     8            -- Mark Twain, "Pudd'nhead Wilson's Calendar"
  10.     9    
  11.     10    Sheriff Chameleotoptor sighed with an air of weary sadness, and then
  12.     11    turned to Doppelgutt and said 'The Senator must really have been on a
  13.     12    bender this time -- he left a party in Cleveland, Ohio, at 11:30 last
  14.     13    night, and they found his car this morning in the smokestack of a British
  15.     14    aircraft carrier in the Formosa Straits.'
  16.     15            -- Grand Panjandrum's Special Award, 1985 Bulwer-Lytton

匹配句首 '^'

  1. ➤ grep -ni '^A' fortune
  2. 1:All generalizations are false, including this one.
  3. 14:aircraft carrier in the Formosa Straits.'

-n 的意思是显示行号


匹配句尾 '$'

  1. ➤ grep -ni '\.$' fortune
  2. 1:All generalizations are false, including this one.
  3. 4:very thin paper.
  4. 7:that think they are truffles.

这里的 '.$' 是以 . 字符结尾的意思, 中间的反斜杠是逃逸字符,起转义的效果

匹配空行 '^$'

  1. ➤ grep '^$' fortune -n
  2. 5:
  3. 9:

任意单个字符 '.'

  1. ➤ grep -n '.re' fortune
  2. 1:All generalizations are false, including this one.
  3. 3:Many pages make a thick book, except for pocket Bibles which are on very
  4. 6:Remark of Dr. Baldwin's concerning upstarts: We don't care to eat toadstools
  5. 7:that think they are truffles.
  6. 11:turned to Doppelgutt and said 'The Senator must really have been on a

\b 的意思是单词分界线,也许是空格,也许是tab


  1. ➤ grep -n '\b.re\b' fortune
  2. 1:All generalizations are false, including this one.
  3. 3:Many pages make a thick book, except for pocket Bibles which are on very
  4. 7:that think they are truffles.

零次或多次重复 '*'

  1. ➤ grep -n 'l*' fortune
  2. 1:All generalizations are false, including this one.
  3. 2:        -- Mark Twain
  4. 3:Many pages make a thick book, except for pocket Bibles which are on very
  5. 4:very thin paper.
  6. 5:
  7. 6:Remark of Dr. Baldwin's concerning upstarts: We don't care to eat toadstools
  8. 7:that think they are truffles.
  9. 8:        -- Mark Twain, "Pudd'nhead Wilson's Calendar"
  10. 9:
  11. 10:Sheriff Chameleotoptor sighed with an air of weary sadness, and then
  12. 11:turned to Doppelgutt and said 'The Senator must really have been on a
  13. 12:bender this time -- he left a party in Cleveland, Ohio, at 11:30 last
  14. 13:night, and they found his car this morning in the smokestack of a British
  15. 14:aircraft carrier in the Formosa Straits.'
  16. 15:        -- Grand Panjandrum's Special Award, 1985 Bulwer-Lytton

显示的不是很好,因为没有高亮什么的.

其实这一部分完全可以当做正则来讲, 毕竟正则才是核心, grep只是一个工具, 怎么用,还是看你的能力如何了.

曾经看过一个30分钟入门正则表达式, 个人感觉挺不错的, 因为我也是从那里入的门, 所以也推荐看这一部分的人也去搜下那个, 作者写的够简单易懂了.

这一段写的有点长, 但是, 当你学会正则的时候你就会发现, 这东西真棒! (这是我BB的, 跟原作者无关哈…)

扩展阅读