Provided by: casper_1.445.3_amd64 bug

NAME

       casper - a hook for initramfs-tools to boot live systems.

SYNOPSIS

       BOOT=casper As kernel parameter boot prompt.

DESCRIPTION

       Casper  is a hook for initramfs-tools used to generate an initramfs capable to boot live systems as those
       created by make-live. This includes the Debian-Live isos, netboot tarballs,  and  usb  stick  images  and
       Ubuntu live cds. At boot time it will look for a (read-only) media containing a "/casper" directory where
       a root filesystems (often a compressed  squashfs)  is  stored.  If  found,  it  will  create  a  writable
       environment, using overlay, for debian like systems to boot from.

RECOGNIZED BOOT OPTIONS

       casper-getty
              This enables a special "serial" login shell (experimental).

       xdebconf
              uses  xdebconfigurator, if present on the rootfs, to configure X instead of the standard procedure
              (experimental).

       hostname=HOSTNAME , userfullname=USERFULLNAME , username=USERNAME
              Those parameters lets you override values read from the config file.

       {keyb|kbd-chooser/method}=KEYBOARD  ,  {klayout|console-setup/layoutcode}=LAYOUT   ,   {kvariant|console-
       setup/variantcode}=VARIANT , {kmodel|console-setup/modelcode}=CODE ,  koptions=OPTIONS
              Configure the running keyboard as specified, if this one misses casper behaves as if "keyb=us" was
              specified. It will be interfered from "locale=" if locale is only 2 lowecase letters as a  special
              case. You could also specify console layout, variant, code, and options (no defaults).

       ip=IFACE,ADDRESS,NETMASK,GATEWAY[:IFACE,ADDRESS,NETMASK,GATEWAY]*
              Let  you specify the name(s) and the options of the interface(s) that should be configured at boot
              time. Do not specify this if you want to use dhcp (default).

       ip[=frommedia]
              If this variable is set, dhcp and static configuration are just skipped and the  system  will  use
              the (must be) media-preconfigured /etc/network/interfaces instead.

       {live-media|bootfrom}=DEVICE
              If you specify one of this two equivalent forms, casper will first try to find this device for the
              "/casper" directory where the read-only  root  filesystem  should  reside.  If  it  did  not  find
              something usable, the normal scan for block devices is performed.

       live-media-offset=BYTES
              This  way  you  could tell casper that your image starts at offset BYTES in the above specified or
              autodiscovered device, this could be useful to hide the debian-live iso or  image  inside  another
              iso or image, to create "clean" images.

       live-media-path=PATH
              Sets  the  path  to  the live filesystem on the medium. By default, it is set to "/casper" and you
              should not change that unless you have customized your media accordingly.

       layerfs-path=PATH
              Sets the path to the leaf layer of  an  overlay-compatible  multi-layer  live  filesystem  on  the
              medium.  By  default,  it  is  not  set  and multi layer is disabled and falls back to the default
              behaviour of casper. A relative path uses "live-mediate-path" as root  directory.  All  the  layer
              images of the same hierarchy must be in the same directory.

       locale=LOCALE | debian-installer/locale=LOCALE
              Configure  the running locale as specified, if not present the live-media rootfs configured locale
              will be used and if also this one misses casper behave as "locale=en_US.UTF-8" was  specified.  If
              only  2  lowercase  letter are specified (like "it"), the "maybe wanted" locale is generated (like
              it:IT.UTF-8), in this case if also "keyb=" is unspecified is set with those  2  lowercase  letters
              (keyb=it).

       netboot[=nfs|cifs|url]
              This tells casper to perform a network mount. The parameter "nfsroot=" (with optional "nfsopts="),
              should specify where is the location of the root filesystem.  With no args, will try  cifs  first,
              and if it fails nfs. If url method is chosen, "url=" parameter should point to the location of the
              ".iso" that will be downloaded and mounted. Note "url=" on the commandline alone, by default  sets
              "netboot=url" method too.

       url=URL
              This  tells  casper  the  download  location  of the installer ISO. The ISO will be downloaded and
              mounted. Networking is required for this option to  work,  which  can  be  configured  with  "ip="
              option. Note, setting this option, will also set "netboot=url" method.

       persistent
              Casper  will  look for persistent and snapshot partitions or files labeled "casper-rw", "home-rw",
              and files called "casper-sn*", "home-sn*" and will try to, in order:  mount  as  /cow  the  first,
              mount  the  second  in  /home,  and  just copy the contents of the latter in appropriate locations
              (snapshots). Snapshots will be tried to be updated on reboot/shutdown. Look at  casper-snapshot(1)
              for more informations.

       nopersistent
              disables  the  above  mentioned "persistent" feature, useful if the bootloader (like syslinux) has
              been installed with persistent enabled.

       persistent-path=PATH
              Casper will look for persistency files in the root directory of a partition. With this  parameter,
              the  path  can  be  configured  so that you can have multiple directories on the same partition to
              store persistency files.

       showmounts
              This parameter will make casper to show on "/" the ro filesystems (mostly compressed) on  /casper.
              This  is  not  enabled by default because could lead to problems by applications like "mono" which
              store binary paths on installation.

       textonly
              Start up to text-mode shell prompts, disabling the graphical user interface.

       todisk=DEVICE
              Adding this parameter, casper will try to copy the entire read-only media to the specified  device
              before  mounting  the  root  filesystem.  It  probably needs a lot of free space. Subsequent boots
              should then skip this step and just specify the "live-media=DEVICE" boot parameter with  the  same
              DEVICE used this time.

       toram  Adding  this  parameter,  casper  will try to copy the whole read-only media to the computer's RAM
              before mounting the root filesystem. This could need a lot of ram, according to the space used  by
              the read-only media.

       {preseed/file|file}=FILE
              A path to a file present on the rootfs could be used to preseed debconf database.

       preseed/allow-network=true
              Bring up the network while running preseed/early_command.

       package/question=VALUE
              All  debian  installed  packages  could  be preseeded from command-line that way, beware of blanks
              spaces, they will interfere with parsing, use a preseed file in this case.

       uuid=UUID
              Check that the discovered medium matches UUID  rather  than  the  default  UUID  embedded  in  the
              initramfs.

       ignore_uuid
              Do not check that any UUID embedded in the initramfs matches the discovered medium.  casper may be
              told to generate a UUID by setting CASPER_GENERATE_UUID=1 when building the initramfs.

       noprompt
              Do not prompt to eject the CD on reboot.

FILES

       /etc/casper.conf some variables can be configured via this config file.

BUGS

       casper works fully on amd64, i386 and ppc, it should also run on other archs.

HOMEPAGE

       Debian Live project <http://live.debian.net/>

SEE ALSO

       casper-snapshot(1),initramfs-tools(8),make-live(8),make-live.conf(5)

AUTHOR

       casper was written by Tollef Fog Heen <tfheen@canonical.com>,  Matt  Zimmerman  <mdz@canonical.com>,  and
       Marco Amadori <marco.amadori@gmail.com>.

       This manual page was written by Marco Amadori <marco.amadori@gmail.com>,
              for the Debian project (but may be used by others).