• Last 5 Forum Topics
    Last post

The Web Only This Site



  • MARC

    Mailing list ARChives
    - Search by -


    Computing Dictionary

  • Text Link Ads

  • LINUX man pages
  • Linux Man Page Viewer

    The following form allows you to view linux man pages.





           Debconf  is  a  configuration  system  for  Debian  packages. /etc/deb-
           conf.conf and ~/.debconfrc are  configuration  files  debconf  uses  to
           determine  which  databases it should use. These databases are used for
           storing two types of information; dynamic config data the  user  enters
           into  it, and static template data. Debconf offers a flexible, extensi-
           ble database backend. New drivers can be  created  with  a  minimum  of
           effort, and sets of drivers can be combined in various ways.


             # This is a sample config file that is
             # sufficient to use debconf.
             Config: configdb
             Templates: templatedb
             Name: configdb
             Driver: File
             Filename: /var/cache/debconf/config.dat
             Name: templatedb
             Driver: File
             Mode: 644
             Filename: /var/cache/debconf/templates.dat


           The  format  of  this file is a series of stanzas, each separated by at
           least one wholly blank line. Comment lines beginning with a "#" charac-
           ter are ignored.
           The  first  stanza of the file is special, is used to configure debconf
           as a whole. Two fields are required to be in this first stanza:
                  Config Specifies the name of the database  from  which  to  load
                         config data.
                         Specifies  the  name  of the database to use for the tem-
                         plate cache.
           Additional fields that can be used include:
                         The frontend Debconf should use, overriding any  frontend
                         set in the debconf database.
                         The  priority Debconf should use, overriding any priority
                         set in the debconf database.
                         The email address Debconf should send mail to if it needs
                         to  make  sure  that the admin has seen an important mes-
                         If set, this will make debconf not display warnings about
                         various  things.   This can be overridden on the fly with
                         the DEBCONF_NOWARNINGS environment variable.
                  Log    Makes debconf log debugging information as  it  runs,  to
                         the  syslog.  The  value  it  is  set to controls that is
                         logged. See Debug, above for an explanation of the values
                         that can be set to control what is logged.
                  Terse  If set to "true", makes some debconf frontends use a spe-
                         cial terse display mode that outputs as little as  possi-
                         ble. Defaults to false. Terse mode may be temporarily set
                         via the DEBCONF_TERSE environment variable.
           For example, the first stanza of a file might look like this:
             Config: configdb
             Templates: templatedb
           Each remaining stanza in the file sets up a database. A database stanza
           begins by naming the database:
             Name: configdb
           Then  it  indicates  what  database  driver  should  be  used  for this
           database.  See DRIVERS, below, for information about what  drivers  are
             Driver: File
           You can indicate that the database is not essential to the proper func-
           tioning of debconf by saying it is not required. This will make debconf
           muddle on if the database fails for some reason.
             Required: false
           You  can  mark any database as readonly and debconf will not write any-
           thing to it.
             Readonly: true
           You can also limit what types of data can go  into  the  database  with
           Accept- and Reject- lines; see ACCESS CONTROLS, below.
           The  remainder of each database stanza is used to provide configuration
           specific to that driver. For example, the Text driver needs to  know  a
           directory to put the database in, so you might say:
             Filename: /var/cache/debconf/config.dat


           A  number of drivers are available, and more can be written with little
           difficulty. Drivers come in two general types.  First  there  are  real
           drivers  -- drivers that actually access and store data in some kind of
           database, which might be on the local filesystem, or on a  remote  sys-
           tem. Then there are meta-drivers that combine other drivers together to
           form more interesting systems. Let's start with the former.
                                 The file to use as the database. This is a
                                 required field.
                          Mode   The permissions to create the file with if
                                 it  does not exist. Defaults to 600, since
                                 the file could contain passwords  in  some
                          Format The format of the file. See FORMATS below.
                                 Defaults to using a rfc-822 like format.
                          Backup Whether a backup should be made of the old
                                 file  before  changing  it.   Defaults  to
                  As example  stanza  setting  up  a  database  using  this
                    Name: mydb
                    Driver: File
                    Filename: /var/cache/debconf/mydb.dat
                  This  database  driver  allows debconf to store data in a
                  hierarchical directory structure. The names of the  vari-
                  ous  debconf  templates  and  questions are used as-is to
                  form directories with files in them. This format for  the
                  database  is  the  easiest  to  browse and fiddle with by
                  hand.  It has very good load and  save  speeds.  It  also
                  typically  occupies  the most space, since a lot of small
                  files and subdirectories do take up some additional room.
                  The following things are configurable for this driver.
                                 The   directory   to  put  the  files  in.
                                 An extension to add to the names of files.
                                 Must   be   set  to  a  non-empty  string;
                                 defaults to ".dat"
                          Format The format of the file. See FORMATS below.
                                 Defaults to using a rfc-822 like format.
                          Backup Whether a backup should be made of the old
                                 file  before  changing  it.   Defaults  to
                  As  example  stanza  setting  up  a  database  using this
                  This driver is configurable in the same ways  as  is  the
                  DirTree driver, plus:
                  Mode   The  permissions to create files with. Defaults to
                         600, since the files could  contain  passwords  in
                         some circumstances.
                  As  example  stanza  setting  up  a  database  using this
                    Name: mydb
                    Driver: PackageDir
                    Directory: /var/cache/debconf/mydb
                  WARNING: This database driver is currently  experimental.
                  Use with caution.
                  This  database  driver accesses a LDAP directory for deb-
                  conf configuration data. Due to the nature of the  beast,
                  LDAP  directories  should  typically be accessed in read-
                  only mode. This is because  multiple  accesses  can  take
                  place,  and it's generally better for data consistency if
                  nobody tries to modify the data while this is  happening.
                  Of  course,  write  access  is  supported for those cases
                  where you do want to update the config data in the direc-
                  For  information  about setting up a LDAP server for deb-
                  conf, read  /usr/share/doc/debconf-doc/README.LDAP  (from
                  the debconf-doc package).
                  To  use  this  database driver, you must have the libnet-
                  ldap-perl package installed. Debconf suggests that  pack-
                  age, but does not depend on it.
                  Please  carefully  consider  the security implications of
                  using a remote debconf database.  Unless  you  trust  the
                  source,  and you trust the intervening network, it is not
                  a very safe thing to do.
                  The following things are configurable for this driver.
                          server The host name or IP  address  of  an  LDAP
                                 server to connect to.
                          port   The  port  on which to connect to the LDAP
                                 server. If none is given, the default port
                                 is used.
                          basedn The  DN  under which all config items will
                                 be  stored.  Each  config  item  will   be
                                 eral case.  Anonymous  binding  should  be
                                 sufficient  most of the time for read-only
                                 access. Specifying a bind DN and  password
                                 should be reserved for the occasional case
                                 where you wish to update the debconf  con-
                                 figuration data.
                                 Enable  access to individual LDAP entries,
                                 instead of fetching them all  at  once  in
                                 the  beginning. This is very useful if you
                                 want to monitor your LDAP  logs  for  spe-
                                 cific debconf keys requested. In this way,
                                 you could also write custom handling  code
                                 on the LDAP server part.
                                 Note that when this option is enabled, the
                                 connection to  the  LDAP  server  is  kept
                                 active  during the whole Debconf run. This
                                 is a little different from the  all-in-one
                                 behavior  where  two brief connections are
                                 made to LDAP; in the beginning to retrieve
                                 all  the  entries,  and in the end to save
                                 eventual changes.
                  An example  stanza  setting  up  a  database  using  this
                  driver,  assuming  the  remote database is on
                  and can be accessed anonymously:
                    Name: ldapdb
                    Driver: LDAP
                    Readonly: true
                    BaseDN: cn=debconf,dc=example,dc=com
                    KeyByKey: 0
                  Another example, this time the LDAP database is on local-
                  host, and can be written to:
                    Name: ldapdb
                    Driver: LDAP
                    Server: localhost
                    BaseDN: cn=debconf,dc=domain,dc=com
                    BindPasswd: secret
                    KeyByKey: 1
                  This special-purpose database driver reads and writes the
                  database from standard input/output. It may be useful for
                  people with special needs.
                  The following things are configurable for this driver.
           That's  all of the real drivers, now moving on to meta-drivers..
                  This driver stacks up a number of other databases (of any
                  type),  and  allows them to be accessed as one. When deb-
                  conf asks for a value, the first database  on  the  stack
                  that  contains  the  value  returns it. If debconf writes
                  something to the database, the write normally goes to the
                  first  driver  on  the stack that has the item debconf is
                  modifying, and if none do, the new item is added  to  the
                  first writable database on the stack.
                  Things become more interesting if one of the databases on
                  the stack is readonly. Consider a stack of the  databases
                  foo,  bar,  and baz, where foo and baz are both readonly.
                  Debconf wants to change an item, and this  item  is  only
                  present  in  baz,  which is readonly. The stack driver is
                  smart enough to realize that won't work, and it will copy
                  the  item  from baz to bar, and the write will take place
                  in bar. Now the item in baz is shadowed by  the  item  in
                  bar, and it will not longer be visible to debconf.
                  This  kind of thing is particularly useful if you want to
                  point many systems at a central, readonly database, while
                  still  allowing  things  to be overridden on each system.
                  When access controls are added  to  the  picture,  stacks
                  allow you to do many other interesting things, like redi-
                  rect all passwords  to  one  database  while  a  database
                  underneath it handles everything else.
                  Only  one  piece  of  configuration is needed to set up a
                          Stack  This is where you specify a list of  other
                                 databases,  by name, to tell it what makes
                                 up the stack.
                  For example:
                    Name: megadb
                    Driver: stack
                    Stack: passworddb, configdb, companydb
                  WARNING: The stack driver is not very  well  tested  yet.
                  Use at your own risk.
                  This  driver  passes  all requests on to another database
                  driver. But it also copies all write requests to a backup
                  database driver.
                    Driver: Backup
                    Db: mydb
                    Backupdb: mybackupdb
                  This  driver  passes  all requests on to another database
                  driver, outputting verbose  debugging  output  about  the
                  request and the result.
                  You  must  specify  the  following  fields to set up this
                          Db     The database to read from and write to.


           When you set up a database, you can  also  use  some  fields  to
           specify  access  controls.  You can specify that a database only
           accepts passwords, for example, or make a database  only  accept
           things with "foo" in their name.
                  As  was mentioned earlier, this access control, if set to
                  "true", makes a database readonly. Debconf will read val-
                  ues from it, but will never write anything to it.
                  The  text  in  this  field  is  a perl-compatible regular
                  expression that is matched against the names of items  as
                  they  are  requested  from the database. Only if an items
                  name matches the regular expression,  will  the  database
                  allow debconf to access or modify it.
                  Like Accept-Name, except any item name matching this reg-
                  ular expression will be rejected.
                  Another regular expression, this matches against the type
                  of  the  item  that  is  being accessed. Only if the type
                  matches the regex will access be granted.
                  Like Accept-Type, except any type matching  this  regular
                  expression will be rejected.


           Some  of  the database drivers use format modules to control the
           actual format in which the database is  stored  on  disk.  These
           formats are currently supported:
             Name: mydb
             Driver: DirTree
             Directory: /var/cache/debconf/config
             # This is another database that I use to hold
             # only X server configuration.
             Name: X
             Driver: File
             Filename: /etc/X11/debconf.dat
             Mode: 644
             # It's sorta hard to work out what questions
             # belong to X; it should be using a deeper
             # tree structure so I could just match on ^X/
             # Oh well.
             Accept-Name: xserver|xfree86|xbase
             # This is our company's global, read-only
             # (for me!) debconf database.
             Name: company
             Driver: LDAP
             BaseDN: cn=debconf,dc=foo,dc=com
             BindDN: uid=admin,dc=foo,dc=com
             BindPasswd: secret
             Readonly: true
             # I don't want any passwords that might be
             # floating around in there.
             Reject-Type: password
             # If this db is not accessible for whatever
             # reason, carry on anyway.
             Required: false
             # I use this database to hold
             # passwords safe and secure.
             Name: passwords
             Driver: File
             Filename: /etc/debconf/passwords
             Mode: 600
             Accept-Type: password
             # Let's put them all together
             # in a database stack.
             Name: stack
             Driver: Stack
             Stack: passwords, X, mydb, company
             # So, all passwords go to the password database.
             # Most X configuration stuff goes to the X
             # database, and anything else goes to my main
             # database. Values are looked up in each of those
             # in turn, and if none has a particular value, it
             # is looked up in the company-wide LDAP database
             # (unless it's a password).
           on the fly, see debconf(7)
           The field names (the part of the line before the colon) is case-
           insensitive. The values, though, are case sensitive.


           More drivers and formats. Some ideas include: A SQL driver, with
           the capability to access a remote database.  A DHCP driver, that
           makes available some special things like hostname,  IP  address,
           and  DNS  servers.  A driver that pulls values out of public DNS
           records TXT fields.  A format that is compatible with the output
           of  cdebconf.   An override driver, which can override the value
           field or flags of all requests that pass through it.






           Joey Hess <>

  • Linux

    The Distributions


    The Software


    The News


  • Toll Free
Copyright © 1999 - 2016 by LinuxGuruz