Linux grep 的基本表达式不支持 \d 吗？
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Is \d not supported by grep's basic expressions?
提问by Ankur Agarwal
This does not generate any output. How come?
这不会产生任何输出。怎么来的？
$ echo 'this 1 2 3' | grep '\d\+'
But these do:
但这些确实：
$ echo 'this 1 2 3' | grep '\s\+'
this 1 2 3
$ echo 'this 1 2 3' | grep '\w\+'
this 1 2 3
采纳答案by Daenyth
grep's default mode is (iirc) POSIX regex, and \dis pcre. You can either pass -Pto gnu grep, for perl-like regexps, or use [[:digit:]]instead of \d.
grep的默认模式是 (iirc) POSIX regex，并且\d是 pcre。您可以通过-P给的GNU grep的类似Perl的正则表达式，或者使用[[:digit:]]替代\d。
daenyth@Bragi ~ $ echo 1 | grep -P '\d'
1
daenyth@Bragi ~ $ echo 1 | grep '[[:digit:]]'
1
回答by Charles Ma
Try this $ echo 'this 1 2 3' | grep '[0-9]\+'
尝试这个 $ echo 'this 1 2 3' | grep '[0-9]\+'
