Reference

update-initramfs(8)

generate an initramfs image

NAME

update-initramfs - generate an initramfs image

SYNOPSIS

update-initramfs {-c|-d|-u} [-k version] [-v] [-b directory] [-s timestamp]
update-initramfs --version
update-initramfs -h

DESCRIPTION

The update-initramfs script manages your initramfs images on your local box. It keeps track of the existing initramfs archives in /boot. There are three modes of operation create, update or delete. You must at least specify one of those modes.

The initramfs is a gzipped cpio archive. At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it as initial root file system. All finding of the root device happens in this early userspace.

OPTIONS

-k version

Set the specific kernel version for whom the initramfs will be generated. For example the output of uname -r for your currently running kernel. This argument is optional for update. The default is the latest kernel version.

The use of "all" for the version string specifies that update-initramfs should operate on all installed kernel versions (with -c), or on all installed kernel versions that already have an initramfs (with -d or -u).

-c

This mode creates a new initramfs.

-u

This mode updates an existing initramfs.

-d

This mode deletes an existing initramfs.

-v

This option increases the amount of information you are given during the chosen action.

-b directory

Set an different bootdir for the image creation.

-s timestamp

This parameter sets a Unix time stamp (seconds since 1970) for the update mode. An existing initramfs will only be updated if it is not newer than the specified Unix time stamp. This parameter will be ignored if set to an empty string.

--version

Print the version information of the underlying initrd generation tool and exit.

-h, --help

Print a short help page describing the available options in update-initramfs.

EXAMPLES

Update the initramfs of the newest kernel:

update-initramfs -u

Create the initramfs for a specific kernel:

update-initramfs -c -k 2.6.18-1-686

FILES

/etc/initramfs-tools/update-initramfs.conf

AUTHOR

The initramfs-tools are written by Maximilian Attems <[email protected]>, Jeff Bailey <[email protected]> and numerous others.

SEE ALSO

initramfs.conf(5), initramfs-tools(7), mkinitramfs(8), lsinitramfs(8).

History

--help since Debian 10 (Buster); --version since Debian 13 (Trixie); -s since Debian 13 (Trixie).

-t until Debian 9 (Stretch).