LINUX-UPDATE-SYMLINKS

Section: User Commands (1)
Updated: 5 June 2016
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NAME

linux-update-symlinks - maintain symlinks to default kernel and initramfs

SYNOPSIS

linux-update-symlinks {install|upgrade|remove} VERSION IMAGE-PATH

DESCRIPTION

linux-update-symlinks is intended to be called from the

postinst and postrm maintainer scripts of Linux kernel packages. The postinst script must pass the first argument install or upgrade depending on whether a fresh installation or an upgrade has taken place.

The VERSION argument must be the kernel version string as shown by uname -r and used in filenames.

The IMAGE-PATH argument must be the absolute filename of the kernel image.

By default, this command maintains symlinks in the root directory. This behaviour can be modified by settings in /etc/kernel-img.conf:

: image_dest Specifies the directory in which to maintain symlinks
link_in_boot: If set to a true value, specifies that the directory is /boot
no_symlinks: If set to a false value, disables maintenance of symlinks

The symlinks for the primary default kernel version are named vmlinuz or vmlinux (depending on whether the architecture normally uses compressed kernel images) and initrd.img (if it uses an initramfs). The symlinks for the secondary default have the same names with the suffix .old.

If symlink maintenance is disabled, linux-update-symlinks does nothing, successfully. Otherwise it makes a list of kernel versions in decreasing order of priority:

•: The given VERSION, if the first argument is install
•: The current primary default version, if it exists and is not already listed
•: The current secondary default version, if it exists and is not already listed
•: All other versions whose files are installed, excluding the specified VERSION if the first argument is remove, in decreasing version order

The top two entries on the list are the new primary and secondary default versions, and it updates the symlinks accordingly. In case there is only one entry, this is both the primary and secondary default version. If there are no entries, there are no default versions and it removes the default symlinks.

ENVIRONMENT VARIABLES

INITRD: When the first argument is install or upgrade, linux-update-symlinks assumes that the given VERSION will use an initramfs unless this variable is set to No.

FILES

/boot/initrd.img-*: Installed initramfs images
/boot/vmlinuz-* | /boot/vmlinux-*: Installed kernel images
/etc/kernel-img.conf: Configuration file specifying whether and where to create symlinks
/initrd.img: Symlink to the initramfs image for the primary default version
/initrd.img.old: Symlink to the initramfs image for the secondary default version
/vmlinuz | /vmlinux: Symlink to the kernel image for the primary default version
/vmlinuz.old | /vmlinux.old: Symlink to the kernel image for the secondary default version

AUTHOR

linux-update-symlinks and this manual page were written by Ben Hutchings as part of the Debian linux-base package.