Provided by: casper_1.394.3_amd64 bug


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


       BOOT=casper As kernel parameter boot prompt.


       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 unionfs, for
       debian like systems to boot from.


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

              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   ,
              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).

              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).

              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.

              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

              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.

              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

       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).

              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.

              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

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

              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.

              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.

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

              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.

              A path to a file present on the rootfs could be used to preseed debconf database.

              Bring up the network while running preseed/early_command.

              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

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

              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.

              Do not prompt to eject the CD on reboot.


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


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


       Debian Live project <>




       casper   was   written   by   Tollef   Fog  Heen  <>,  Matt  Zimmerman
       <>, and Marco Amadori <>.

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