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Casper és un paquet de programari que permet als sistemes Linux basats en initramfs arrancar des de dispositius de només lectura.

Instal·lació

$ sudo apt-get install casper 

Documentació

$ man casper 
CASPER(7)                                                                   Initramfs-tools hook                                                                   CASPER(7)

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  filesys‐
      tems (often a compressed squashfs) is stored. If found, it will create a writable environment, using unionfs, 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.

      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]
             This  tells  casper to perform a network mount. The parameter "nfsroot=" (with optional "nfsopts="), should specify where is the location of the root filesys‐
             tem.  With no args, will try cifs first, and if it fails nfs.

      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 prob‐
             lems 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.

      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 <[email protected]>, Matt Zimmerman <[email protected]>, and Marco Amadori <[email protected]>.

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

1.69                                                                          Thu,  28 Sep 2006                                                                    CASPER(7)

Exemples

Arrancar Ubuntu en RAM

Vegeu també

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