bash 如何在不转义的情况下grep星号？
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How to grep asterisk without escaping?
提问by Michael
Suppose I have a file abc.txtwhich contains line ab*cd. When I grepthat pattern ab*cdwith quotes but without escaping the asterisk it does not work:
假设我有一个abc.txt包含 line的文件ab*cd。当我使用引号但没有转义星号的grep模式时ab*cd，它不起作用：
> grep ab*c abc.txt > grep "ab*c" abc.txt > grep 'ab*c' abc.txt
When I use bothquotes and escaping it doeswork
当我使用这两个引号和逃避它确实工作
> grep "ab\*c" abc.txt ab*cd > grep 'ab\*c' abc.txt ab*cd
Now I wonder why the quotes do not work and if I can use onlyquotes without escaping the asterisk.
现在我想知道为什么引号不起作用，以及我是否可以只使用引号而不转义星号。
回答by Rubens
Use the flag -Fto search for fixed strings -- instead of regular expressions. From man grep:
使用标志-F来搜索固定字符串——而不是正则表达式。来自man grep：
-F, --fixed-strings
Interpret PATTERN as a list of fixed strings, separated by
newlines, any of which is to be matched. (-F is specified by
POSIX.)
For example:
例如：
$ grep -F "ab*c" <<< "ab*c"
ab*c
回答by Kent
first of all, you should keep in mind: regex =/= glob
首先，你应该记住： regex =/= glob
*has special meaning in regex. You have to escape it to match it literally. without escaping the *, grep tries to match ab+(any number of b)+c
*在正则表达式中具有特殊意义。你必须逃避它才能真正匹配它。没有转义*，grep 会尝试匹配ab+(any number of b)+c
for example:
例如：
abbbbbbbbbbbbc
abbbbbbbbbbbbc
