bf(Options) this must be specified in list notation. The commands
are invoked in order using /bin/sh, should any fail APT will abort.
+dit(bf(BPre-Install-Pkgs))
+This is a list of shell commands to run before invoking dpkg. Like
+bf(Options) this must be specified in list notation. The commands
+are invoked in order using /bin/sh, should any fail APT will abort.
+Apt will pass to the commands on standard input the filenames of all
+.deb files it is going to install, one per line.
+
dit(bf(Run-Directory))
APT chdirs to this directory before invoking dpkg, the default is /.