Following up on the little project I was trying to name in January which naturally snowballed into a larger project, Sys::Export has finally reached CPAN viability!

From the synopsis:

  use Sys::Export::CPIO;
  use Sys::Export -src => '/', -dst => Sys::Export::CPIO->new("initrd.
+cpio");
  
  rewrite_path '/sbin'     => '/bin';
  rewrite_path '/usr/sbin' => '/bin';
  rewrite_path '/usr/bin'  => '/bin';
  
  add '/bin/busybox';
  add ...;
  finish;
[download]

I even have a test (gated by environment variables) which can generate the initrd by exporting pieces of an Alpine docker container, and then run Linux with that initrd inside qemu.