febootstrap-to-initramfs - Convert febootstrap root to initramfs (cpio)
febootstrap-to-initramfs [--files=filelist] DIR > initrd.img
febootstrap-to-initramfs converts the filesystem created by
febootstrap(8) into an initramfs image. This allows the new system to
be booted on real hardware or inside a QEMU-based virtual machine.
An initramfs image is just a compressed cpio file, so you could
uncompress it with gunzip(1) and use cpio(1) to convert it into other
The permissions inside the initrd image are corrected automatically
(see the discussion of fakeroot logfile in the febootstrap(8) page).
You do not need to run this command as root.
"filelist" should be a file containing a list of the files to be
added to the initramfs (one per line). Only those files are added
and any others are ignored.
When the "--files" option is not given, all files in "DIR" are
added to the initramfs image.
This prevents the initramfs image from being compressed.
Linux can boot from uncompressed initramfs images (in fact,
faster), but they take up a lot more space on disk.
Normal initramfs images start by executing the program or script called
"/init". febootstrap does not create this script, so you may wish to,
particularly for very minimal bootstraps that don’t have the normal
SysVinit/upstart machinery. It’s also required if the kernel cannot
find a "real" root filesystem (the root filesystem that we built and
placed in an initramfs doesn’t count).
Linux will try to run the following commands in turn, unless you
override it using the "init=cmd" kernel option:
Initramfs images are uncompressed by the kernel into memory. When
booting the new system you will need at least enough free RAM to store
the uncompressed filesystem plus extra to run any programs. Bear this
in mind when creating very large filesystems.
Richard W.M. Jones <rjones @ redhat . com>
(C) Copyright 2009 Red Hat Inc.,
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
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This program is distributed in the hope that it will be useful, but
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