如何显示从一个包到另一个包的依赖关系链？

Question

例如，我想找出为什么monodevelop依赖于systemd.

apt-rdepends -r systemd显示所有直接或间接依赖于 systemd 的包：

$ apt-rdepends --dotty -r systemd | grep monodevelop
"monodevelop" -> "libgnome2.24-cil";
...

debtree monodevelop显示monodevelop直接或间接依赖的所有包：

$ debtree monodevelop | grep -- '-> "systemd"'
"libpam-systemd" -> "systemd" [color=blue,label="(= 215-6)"];
...

monodevelop但是我如何轻松地显示从到 的链systemd？

其中一条链的示例：

monodevelop -> libgnome2.24-cil -> libgnome2-0 -> gvfs -> gvfs-daemons ->  udisks2 -> libpam-systemd -> systemd

Answer 1

为此开发了一个oneliner：

$ apt-rdepends --dot -r systemd | perl -ne 'our %chains; if(m!"([^"]+)" -> "([^"]+)"[^"]*;!) { my $c="$2 $chains{$2}"; $chains{$1}=$c; print "$1 $c\n" }'  | grep '^monodevelop '
Reading package lists... Done
Building dependency tree       
Reading state information... Done
monodevelop libgnome2.24-cil libgnomeui-0 libbonoboui2-0 libgnome2-0 gvfs gvfs-daemons udisks2 libpam-systemd systemd