Bash 被覆盖。使用 Dash，apt-get --reinstall install bash 返回错误

Question

所以，我/bin/bash不小心用一个愚蠢的 bash 脚本覆盖了。我之前的问题可以在下面找到。建议我创建一个新的来处理出现的问题。回顾一下，我能够使用 GUI 将我的默认终端更改为 dash，我可以在其中运行命令。现在，我正在尝试重新安装 bash，以便我可以将默认终端改回。如前所述，我正在运行apt-get --reinstall installbash，它应该重新安装它。但是，它返回一个错误：

    reading package lists...
Building dependency tree...
Reading state information...
The following additional packages will be installed:
  bash-completion
Suggested packages:
  bash-doc
The following packages will be upgraded:
  bash bash-completion
2 upgraded, 0 newly installed, 0 to remove and 2128 not upgraded.
2 not fully installed or removed.
Need to get 0 B/1,605 kB of archives.
After this operation, 673 kB of additional disk space will be used.
Do you want to continue? [Y/n] (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
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(Reading database ... 100%
(Reading database ... 307792 files and directories currently installed.)
Preparing to unpack .../archives/bash_4.4-5_amd64.deb ...
dpkg (subprocess): unable to execute old pre-removal script (/var/lib/dpkg/info/bash.prerm): No such file or directory
dpkg: warning: subprocess old pre-removal script returned error exit status 2
dpkg: trying script from the new package instead ...
dpkg (subprocess): unable to execute new pre-removal script (/var/lib/dpkg/tmp.ci/prerm): No such file or directory
dpkg: error processing archive /var/cache/apt/archives/bash_4.4-5_amd64.deb (--unpack):
 subprocess new pre-removal script returned error exit status 2
dpkg (subprocess): unable to execute installed post-installation script (/var/lib/dpkg/info/bash.postinst): No such file or directory
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/bash_4.4-5_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

此外，dpkg --configure bash说它在处理包时出错，并且 bash “处于非常糟糕的不一致状态；您应该在尝试配置之前重新安装它。”

我正在运行的发行版是 Kali 2.2 滚动版，我已经知道我会对这个发行版产生很多仇恨，因为如果有的话，覆盖 bash 是一个错误。

新帖子，由@Philippos 推荐。旧帖子的链接在这里

Answer 1

问题是 bash prerm 脚本使用 bash，因此它无法运行导致整个重新安装失败。

有多种方法可以解决这个问题：

1) 我的系统（Debian 不稳定版和 Debian 稳定版）上的 bash prerm 脚本非常简单，不需要 bash 来运行。因此，只需编辑/var/lib/dpkg/info/bash.prerm并将第一行从 更改#! /bin/bash为#! /bin/sh。还要确保/bin/sh不指向bash( ls -l /bin/sh)。如果是，则您可能已/bin/dash安装，因此请尝试编辑 prerm 文件以使用该文件。

2) 删除prerm 文件并重新安装。prerm 文件在 Debian 4.4-5 版本中没有任何重要作用，因此您可以删除 prerm 文件并尝试重新安装。

3) 您可以/bin/bash从.deb已经下载的存档中提取。您可以在输出中看到路径：/var/cache/apt/archives/bash_4.4-5_amd64.deb. 这是一个ar(1)包含三个文件的存档：

• debian-binary
• control-tar.gz
• data.tar.xz

请注意，该data.tar文件可能不是xz压缩文件——还有其他格式——gzip、bzip 等。我假设它是一个xz文件，但如果不是，您可以适当地替换该后缀和 zcat 程序。

您可以.deb通过运行来查看文件的内容：

$ ar t /var/cache/apt/archives/bash_4.4-5_amd64.deb
debian-binary
control.tar.gz
data.tar.xz

您可以data.tar.xz通过运行来查看文件的内容：

$ ar p /var/cache/apt/archives/bash_4.4-5_amd64.deb data.tar.xz | xzcat | tar tvf -
...
./bin/bash
...

你可以从中提取/bin/bash：

$ cd /tmp
$ ar p /var/cache/apt/archives/bash_4.4-5_amd64.deb data.tar.xz | xzcat | tar xvf - ./bin/bash

既然你从/tmp. 您现在将拥有文件/tmp/bin/bash. 您可以将其复制回/bin并再次覆盖 bash，但这次有一些不错的内容。

有dpkg的工具，你可以用它来操作.deb文件，但因为它们是简单的档案，我觉得更容易记住如何使用ar(1)，并tar(1)相对于dpkg的特定选项。