tricksandtips.md

u-root Tricks and Tips

Here are some things we do that you might find useful.

Pipe u-root output to stdout

One thing to keep in mind is that on many systems, now, standard out is a named file you can write to. Further, you can create a cpio that has no Linux initramfs content. Finally, you can merge cpios to form a more comprehensive cpio.

inventory the cpio archive without creating it.

u-root -o /dev/stdout | cpio -ivt

Make a pure u-root cpio with no other files.

u-root -base /dev/null

Make an image that is BOTH dynamic and busybox

Well, it almost works ... help wanted.

Because busybox binaries go in /bbin and source binaries go in /ubin. This is useful because you can get a faster boot but still have a Go toolchain

u-root -base /dev/null -o /tmp/busybox.cpio
u-root -base /tmp/busybox.cpio -build source -o combined.cpio

To see what that looks like:

cpio -ivt < combined.cpio

You can use testramfs to run it and watch it fork-bomb itself on init. So close! Working on it.