正則表達式備忘錄
Regular Expressions Cheatsheet中文版
原文：https://www.maketecheasier.com/cheatsheet/regex/
| 測試文件a.txt |
| 0x1: If you work with text, you’ll appreciate how useful regular expressions are. 0x00001: Regular expressions are everywhere in Linux for searching through text right down to the character. 0x0000001: This Regular Expressions cheatsheet will be useful for people who simply need a little refresher from time to time. |
| 字符 |
描述 |
例子 |
|
| . (點) |
任何單個字符，除了換行(\n) |
c.t 匹配 "cat", "cut" 或 "cot."。 '任意字符加im'： [root@test: /tmp]# egrep '.im' a.txt who simply need a little refresher from time to time. |
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| * (星號) |
重復前一個表達式0或多次 |
12*3 匹配 "13", "123", "1223", "12223"。 與 . 合用代表任何字符。 m.*easier 匹配 "maketecheasier"。 'x加任意個0加1:' [root@test: /tmp]# egrep 'x0*1:' a.txt 0x1: 0x00001: 0x0000001: '任何包含f加任意字符加l' [root@test: /tmp]# egrep 'f.*l' a.txt how useful regular expressions are. will be useful for people |
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| + (加號) |
重復前一個表達式1或多次 |
12+3 匹配 "123","1223","12223" 'x加至少一個0加1:' （比較上一個用*的） [root@test: /tmp]# egrep 'x0+1:' a.txt 0x00001: 0x0000001: |
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| ? (問號) |
前一個字符可有可無 |
ma?ke 匹配 "make", "mke" '有n或無n加ee' [root@test: /tmp]# egrep 'n?ee' a.txt This Regular Expressions cheatsheet who simply need a little refresher |
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| ^ (尖號) |
匹配字符串的開頭 |
^he 匹配以he開頭的 "hello", "hell", "help", "he is a boy" '以空格開頭的行' [root@test: /tmp]# egrep '^ ' a.txt how useful regular expressions are. are everywhere in Linux for searching through text right down to the character. will be useful for people who simply need a little refresher from time to time. |
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| $ (美刀) |
匹配字符串的結尾 |
ed$ 匹配以ed結尾的 "acted", bed", "greed" '字母e結尾的行' [root@test: /tmp]# egrep 'e$' a.txt you’ll appreciate from time |
|
| (...) (小括號) |
匹配字符組合 |
(ak) 匹配 "make", "take" '包含 it 的' [root@test: /tmp]# egrep '(it)' a.txt If you work with text, who simply need a little refresher |
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| {n} (大括號，n是大於0的整數) |
重復前一個字符n次，n>0 |
12{3}5 匹配 "12225" 'x加4個0加1' [root@test: /tmp]# egrep 'x0{4}1' a.txt 0x00001: |
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| [...] (中括號) |
匹配里面的任意一個字符 |
[abc] 匹配字符串"abc"中的"a","b" 或 "c" '所有包含v或b的' [root@test: /tmp]# egrep '[vb]' a.txt are everywhere in Linux will be useful |
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| [^...] |
匹配任意字符，除了里面定義的 |
a[^b]c 匹配 "aec", "acc", "adc", 但不匹配 "abc" 'f前面不能是空格或e' [root@test: /tmp]# egrep '[^ e]f' a.txt If you work with text, |
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| | (管道符) |
匹配管道符分隔的任一字符串 |
col(o|ou)r 匹配 "color", "colour"
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| - (連字符) |
指定某個范圍內的字符一般是[a-z],[A-Z],[1-9],[a-zA-Z1-9] |
a[a-z]c 匹配 "abc", "acc", "adc" |
|
| \ (反斜線) |
轉義符，將特殊符合轉義為符號本身 |
a\*c 匹配 "a*c". |
|
| \n, \r, \t |
代表 換行，回車，制表符 |
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| \b...\b |
匹配整個單詞 |
\bTech\b 匹配 the word "Tech" in "Make Tech Easier". 找到單詞time [root@test: /tmp]# egrep '\btime\b' a.txt from time to time. |
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