SED前pression，焦XX：因连字符范围无效年底错误 [英] sed expression , char xx: Invalid range end error caused by hyphen

问题描述

给定一个文件：

2014-08-01 20:13:17.666 xxxxxxxxxx
2014-08-01 20:13:17.666 xxxxxxxxxx
2014-08-01 20:13:17.666 xxxxxxxxxx
......

我试图用去除微秒sed的：

I am attempting to remove the microseconds using sed:

GNU sed version 4.2.1
Copyright (C) 2009 Free Software Foundation, Inc.

以下是与错误信息失败的sed：-e前pression＃1，烧焦38：无效的范围到底

The following is failing with error message "sed: -e expression #1, char 38: Invalid range end"

sed 's/\([0-9][0-9\- :]*\)\.[0-9]\{3\}/\1/g' < a.csv

然而，六a.csv和搜索

However, vi a.csv and searching for

\([0-9][0-9\- :]*\)\.[0-9]\{3\}

正常工作。

的根本原因是逃脱连字符。如果我删除了逃跑连字符的sed不会抱怨，但它不会匹配预期的格局。我试图逃避连字符无济于事的不同方法。

The rootcause is the escaped hyphen. If I remove the escaped hyphen, sed won't complain but it won't match the intended pattern. I have tried different ways of escaping the hyphen to no avail.

解决方法是明确地写出整个日期时间格式如下：

The workaround is to explicitly write out the entire date-time format as follows:

sed 's/\([0-9][0-9]*-[0-9][0-9]-[0-9][0-9] [0-2][0-9]:[0-5][0-9]:[0-5][0-9]\)\.[0-9]\{3\}/\1/g'

解决方法似乎丑陋和繁琐。我不知道底层RE引擎是SED和vi不同。不过，我喜欢

The workaround seems ugly and cumbersome. I do realize the underlying RE engine is different between sed and vi. However, I like to

1. 明白为什么连逃跑的连字符SED
失败

2. 如何修改为RE SED，使其更加优雅。

相关，但不是由， sed的错误＆QUOT解决;无效的范围到底＆QUOT;

推荐答案

在字符类，连字符必须是第一个或最后一个。试图用一个反斜杠逃脱它不工作（，而增加了反斜杠对类）。

In a character class, the hyphen must be first or last. Attempting to escape it with a backslash does not work (and instead adds the backslash to the class).

有多个 SED 方言和工作方式不同其他多个正则表达式实现，但在这种情况下，诊断是相当琐碎。与此修复程序：

There are multiple sed dialects and multiple other regex implementations which work differently, but in this case, the diagnostic is fairly trivial. And the fix:

sed 's/\([0-9][-0-9 :]*\)\.[0-9]\{3\}/\1/' < a.csv

（我也删除了 / G 标志，因为它似乎是多余的在这里。当然，你必须每这种模式的行不超过一个发生？）

(I also removed the /g flag because it appears to be redundant here. Surely, you have no more than one occurrence per line of this pattern?)

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