如何在BSD tar路径替换选项中转义字符 [英] How to escape chars in BSD tar path substitution option

问题描述

这不起作用：

$ tar -cf /tmp/z.tar -C /space/myroot -s '/^\.svn\/patches/__patches' src .svn/patches
tar: Invalid regular expression: trailing backslash (\)

也不好：

Also no good:

$ tar -cf /tmp/z.tar -C /space/myroot -s '/^\\.svn\\/patches/__patches' src .svn/patches
tar: Invalid replacement flag _

反斜杠（最多4个）和引号的每个组合都给了我这两个错误之一。但是我知道第一个在sed中起作用：

Every combination of backslashes (up to 4) and quoting gives me one of those two errors. However I know the first one works in sed:

$ tar -cf /tmp/z.tar -C /space/myroot src .svn/patches
$ tar -tf /tmp/z.tar | sed 's/^\.svn\/patches/__patches/'
src/a.c
src/b.c
__patches/A.patch
__patches/B.patch

我也知道我可以解决这个问题：

Also I know I can cop-out and do this:

$ tar -cf /tmp/z.tar -C /space/myroot -s '/^.svn.patches/__patches' src .svn/patches

-但我真的不想要。

-- but I don't really want to.

推荐答案

来自人bsdtar ：

-s模式

....

其中old是基本正则表达式

...

-s pattern
....
where old is a basic regular expression
...

基本正则表达式应该与一起使用\ / 。不幸的是， bsdtar 在这里写错了，并且不能正确处理转义。

Basic regular expression should work with \/. Sadly bsdtar is incorrectly written here, and does not handle escaping correctly.

从 bsdtar / subst.c ：

end_pattern = strchr(rule_text + 1, *rule_text);

rule_text 是字符串 char * 与您传递给 -s 选项的字符串一起传递，因此它具有字符串 / ^ s.svn\ / patches / __ patches 。 end_pattern 应该指向该模式的最后一个字符（即<$ c $中的 / c> / __补丁）。但是，由于使用了简单的strchr，所以使用了找到的第一个 / （ \ / 中的字符）是否使用它。错误：

rule_text is a string char * which is passed with the string you pass to -s option, so it has the string /^\.svn\/patches/__patches. The end_pattern should point to the last character of the pattern (ie. to the / in from of /__patches). However as simple strchr is used, so the first / found is used (the character in \/), escaped or not, it is used. The error:

tar: Invalid regular expression: trailing backslash (\)

来自 regcomp 尝试解析正则表达式 ^ \.svn\ （因为这是两个 / ）。由于表达式中的尾部反斜杠 \ 后面没有任何内容，因此会引发错误（并且正确-尾部有反斜杠）。可以考虑向bsdtar开发人员发布错误报告，但这可能真的不值得修复。

comes from regcomp trying to parse the regular expression ^\.svn\ (as this is the part stripped between the two /). As there is nothing behind the trailing backslash \ in the expression, it throws an error (and is correct - a trailing backslash is there). One could think of posting a bug report to bsdtar developers, but it's probably not really worth fixing.

请注意， -s的语法是 /旧/新/ 。模式中缺少尾随的 / ，您将丢失。在最后一个 / 之后，您可以指定标志。

Note that the syntax for -s is /old/new/. There is a trailing / in the pattern, which you are missing. After the last / you can specify flags.

但是，您可以使用以下方法解决该问题：

You can however workaround the issue with:

bsdtar -s '#\.svn/patches#__patches#'

任何字符都可用于 / 。

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