如何识别 apt-cache show 输出中显示的软件包的 Debian 分支`？

Question 1

apt-cache show不会告诉您它描述的是哪个“分支”，但apt show会：

$ apt show -a tmux
Package: tmux
Version: 3.1c-1
Priority: optional
Section: admin
Maintainer: Romain Francoise <[email protected]>
Installed-Size: 850 kB
Depends: libc6 (>= 2.27), libevent-2.1-7 (>= 2.1.8-stable), libtinfo6 (>= 6), libutempter0 (>= 1.1.5)
Homepage: https://tmux.github.io/
Tag: hardware::input:keyboard, implemented-in::c, interface::text-mode,
 role::program, scope::application, works-with::software:running
Download-Size: 362 kB
APT-Sources: http://deb.debian.org/debian testing/main amd64 Packages
Description: terminal multiplexer
 tmux enables a number of terminals (or windows) to be accessed and
 controlled from a single terminal like screen. tmux runs as a
 server-client system. A server is created automatically when necessary
 and holds a number of sessions, each of which may have a number of
 windows linked to it. Any number of clients may connect to a session,
 or the server may be controlled by issuing commands with tmux.
 Communication takes place through a socket, by default placed in /tmp.
 Moreover tmux provides a consistent and well-documented command
 interface, with the same syntax whether used interactively, as a key
 binding, or from the shell. It offers a choice of vim or Emacs key
 layouts.

Package: tmux
Version: 2.8-3
Priority: optional
Section: admin
Maintainer: Romain Francoise <[email protected]>
Installed-Size: 697 kB
Depends: libc6 (>= 2.27), libevent-2.1-6 (>= 2.1.8-stable), libtinfo6 (>= 6), libutempter0 (>= 1.1.5)
Homepage: https://tmux.github.io/
Tag: hardware::input:keyboard, implemented-in::c, interface::text-mode,
 role::program, scope::application, works-with::software:running
Download-Size: 302 kB
APT-Manual-Installed: yes
APT-Sources: http://deb.debian.org/debian buster/main amd64 Packages
Description: terminal multiplexer
 tmux enables a number of terminals (or windows) to be accessed and
 controlled from a single terminal like screen. tmux runs as a
 server-client system. A server is created automatically when necessary
 and holds a number of sessions, each of which may have a number of
 windows linked to it. Any number of clients may connect to a session,
 or the server may be controlled by issuing commands with tmux.
 Communication takes place through a socket, by default placed in /tmp.
 Moreover tmux provides a consistent and well-documented command
 interface, with the same syntax whether used interactively, as a key
 binding, or from the shell. It offers a choice of vim or Emacs key
 layouts.

查找这些APT-Sources行：它们指示信息对应于哪个存储库。

Answer

apt-cache show不会告诉您它描述的是哪个“分支”，但apt show会：

$ apt show -a tmux
Package: tmux
Version: 3.1c-1
Priority: optional
Section: admin
Maintainer: Romain Francoise <[email protected]>
Installed-Size: 850 kB
Depends: libc6 (>= 2.27), libevent-2.1-7 (>= 2.1.8-stable), libtinfo6 (>= 6), libutempter0 (>= 1.1.5)
Homepage: https://tmux.github.io/
Tag: hardware::input:keyboard, implemented-in::c, interface::text-mode,
 role::program, scope::application, works-with::software:running
Download-Size: 362 kB
APT-Sources: http://deb.debian.org/debian testing/main amd64 Packages
Description: terminal multiplexer
 tmux enables a number of terminals (or windows) to be accessed and
 controlled from a single terminal like screen. tmux runs as a
 server-client system. A server is created automatically when necessary
 and holds a number of sessions, each of which may have a number of
 windows linked to it. Any number of clients may connect to a session,
 or the server may be controlled by issuing commands with tmux.
 Communication takes place through a socket, by default placed in /tmp.
 Moreover tmux provides a consistent and well-documented command
 interface, with the same syntax whether used interactively, as a key
 binding, or from the shell. It offers a choice of vim or Emacs key
 layouts.

Package: tmux
Version: 2.8-3
Priority: optional
Section: admin
Maintainer: Romain Francoise <[email protected]>
Installed-Size: 697 kB
Depends: libc6 (>= 2.27), libevent-2.1-6 (>= 2.1.8-stable), libtinfo6 (>= 6), libutempter0 (>= 1.1.5)
Homepage: https://tmux.github.io/
Tag: hardware::input:keyboard, implemented-in::c, interface::text-mode,
 role::program, scope::application, works-with::software:running
Download-Size: 302 kB
APT-Manual-Installed: yes
APT-Sources: http://deb.debian.org/debian buster/main amd64 Packages
Description: terminal multiplexer
 tmux enables a number of terminals (or windows) to be accessed and
 controlled from a single terminal like screen. tmux runs as a
 server-client system. A server is created automatically when necessary
 and holds a number of sessions, each of which may have a number of
 windows linked to it. Any number of clients may connect to a session,
 or the server may be controlled by issuing commands with tmux.
 Communication takes place through a socket, by default placed in /tmp.
 Moreover tmux provides a consistent and well-documented command
 interface, with the same syntax whether used interactively, as a key
 binding, or from the shell. It offers a choice of vim or Emacs key
 layouts.

查找这些APT-Sources行：它们指示信息对应于哪个存储库。

Question 2

你几乎已经受够了apt-cache policy。您只需将包名称附加到该命令行即可。

您可以用来apt-cache policy [package...]显示安装的版本、默认安装候选版本以及可安装的所有版本（根据您的sources.list文件和固定配置或APT::Default-Release设置）。

例如，在我的一个系统上，默认配置为使用sidaka unstable（由于APT::Default-Release "unstable";my 中的行/etc/apt/apt.conf），并且还允许从中挑选软件包experimental：

$ apt-cache policy tmux
tmux:
  Installed: 3.1c-1
  Candidate: 3.1c-1
  Version table:
     3.2~rc4-1 1
          1 http://ftp.au.debian.org/debian experimental/main amd64 Packages
 *** 3.1c-1 990
        990 http://ftp.au.debian.org/debian unstable/main amd64 Packages
        100 /var/lib/dpkg/status

“已安装”是当前安装的版本。 “候选”是根据您的 apt 配置可以安装的版本（在这种情况下，候选版本已经安装）。 “版本表”显示所有可用版本。

可以通过指定确切的版本号或在您的sources.list文件之一中定义的目标版本来安装任何其他版本。例如，stable、testing、sid、experimental 或特定 debian 版本的名称，如“stretch”或“buster”。

例如，以下之一：

apt install tmux=3.2~rc4-1

apt -t experimental install tmux

apt install tmux/experimental

apt-cache policy顺便说一句，您还可以使用该选项覆盖显示的安装候选版本-t target_release。这在脚本中可能比从命令行运行的东西更有用，可以轻松使用grep -oP '^ +Candidate: \K.*'或提取候选版本awk -F': ' '/^ +Candidate:/ {print $2}'。

Answer