📅 最后修改于: 2020-12-08 05:06:08 🧑 作者: Mango
正则表达式也称为regex或regexp 。它是Linux中非常强大的工具。正则表达式是遵循某种模式的匹配字符串的模式。
正则表达式可用于各种程序，例如grep，sed，vi，bash，重命名等。
正则表达式可以具有一个或几个重复的元字符。
| Metacharacter | Description |
|---|---|
| . | Replaces any character. |
| ^ | Matches start of string and represents characters not in the string. |
| $ | Matches end of string. |
| * | Matches zero or more times the preceding character. |
| \ | Represents the group of characters. |
| () | Groups regular expressions. |
| ? | Matches exactly one character. |
| + | Matches one or more times the preceding character. |
| {N} | Preceding character is matched exactly N times. |
| {N,} | Preceding character is matched exactly N times or more. |
| {N,M} | Preceding character is matched exactly N times, but not more than N times. |
| – | Represents the range. |
| \b | Matches empty string at the edge of a word. |
| \B | Matches empty string if it is not at the edge of a word. |
| \< | Matches empty string at the beginning of a word. |
| \> | Matches empty string at the end of a word. |
正则表达式语法有三种版本：
根据工具或程序，可以使用这些版本中的一个或多个。