How to edit RAM disk images

I really want to read more about how this nash/lvm stuff works on my server…

Editing Ramdisks (initrds)

Following are the steps that enable one to edit a ramdisk for any changes:

1. gunzip -c /boot/initrd-.img >initrd.img
2. mkdir tmpDir
3. mount -o loop initrd.img tmpDir/
4. cd tmpDir
5. Make all necessary changes (copy over modules, edit linuxrc etc)
6. umount tmpDir
7. gzip -9c initrd.img >/boot/initrd-.img

(stolen from ​http://openssi.org/cgi-bin/view?page=docs2/1.2/README.edit-ramdisk )

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Follow-up

At some point, they stopped making them loopback ISOs and now they are just a compressed cpio archive:

 mkdir initrd
 cd initrd/
 gzip -dc /boot/initrd-2.6.23-0.104.rc3.fc8.img | cpio -id

The cpio is in the "new" format, so when recompressing, you need to use --format='newc' .

(stolen from ​http://fedoraproject.org/wiki/KernelCommonProblems )