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APT.CONF(5) APT.CONF(5)
NAME
apt.conf - Configuration file for APT
DESCRIPTION
apt.conf is the main configuration file for the APT suite of tools, all tools make use of
the configuration file and a common command line parser to provide a uniform environment.
When an APT tool starts up it will read the configuration specified by the APT_CONFIG
environment variable (if any) and then read the files in Dir::Etc::Parts then read the
main configuration file specified by Dir::Etc::main then finally apply the command line
options to override the configuration directives, possibly loading even more config files.
The configuration file is organized in a tree with options organized into functional
groups. option specification is given with a double colon notation, for instance
APT::Get::Assume-Yes is an option within the APT tool group, for the Get tool. options do
not inherit from their parent groups.
Syntactically the configuration language is modeled after what the ISC tools such as bind
and dhcp use. Lines starting with // are treated as comments (ignored), as well as all
text between /* and */, just like C/C++ comments. Each line is of the form
APT::Get::Assume-Yes "true"; The trailing semicolon is required and the quotes are
optional. A new scope can be opened with curly braces, like:
APT {
Get {
Assume-Yes "true";
Fix-Broken "true";
};
};
with newlines placed to make it more readable. Lists can be created by opening a scope and
including a single word enclosed in quotes followed by a semicolon. Multiple entries can
be included, each separated by a semicolon.
DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
In general the sample configuration file in /usr/share/doc/apt/examples/apt.conf
/usr/share/doc/apt/examples/configure-index.gz is a good guide for how it should look.
The names of the configuration items are not case-sensitive. So in the previous example
you could use dpkg::pre-install-pkgs.
Two specials are allowed, #include and #clear #include will include the given file, unless
the filename ends in a slash, then the whole directory is included. #clear is used to
erase a list of names.
All of the APT tools take a -o option which allows an arbitrary configuration directive to
be specified on the command line. The syntax is a full option name (APT::Get::Assume-Yes
for instance) followed by an equals sign then the new value of the option. Lists can be
appended too by adding a trailing :: to the list name.
THE APT GROUP
This group of options controls general APT behavior as well as holding the options for all
of the tools.
Architecture
System Architecture; sets the architecture to use when fetching files and parsing
package lists. The internal default is the architecture apt was compiled for.
Default-Release
Default release to install packages from if more than one version available. Contains
release name or release version. Examples: 'stable', 'testing', 'unstable', '4.0',
'5.0*'. Release codenames ('etch', 'lenny' etc.) are not allowed now. See also
apt_preferences(5).
Ignore-Hold
Ignore Held packages; This global option causes the problem resolver to ignore held
packages in its decision making.
Clean-Installed
Defaults to on. When turned on the autoclean feature will remove any packages which
can no longer be downloaded from the cache. If turned off then packages that are
locally installed are also excluded from cleaning - but note that APT provides no
direct means to reinstall them.
Immediate-Configure
Disable Immediate Configuration; This dangerous option disables some of APT's ordering
code to cause it to make fewer dpkg calls. Doing so may be necessary on some extremely
slow single user systems but is very dangerous and may cause package install scripts
to fail or worse. Use at your own risk.
Force-LoopBreak
Never Enable this option unless you -really- know what you are doing. It permits APT
to temporarily remove an essential package to break a Conflicts/Conflicts or
Conflicts/Pre-Depend loop between two essential packages. SUCH A LOOP SHOULD NEVER
EXIST AND IS A GRAVE BUG. This option will work if the essential packages are not tar,
gzip, libc, dpkg, bash or anything that those packages depend on.
Cache-Limit
APT uses a fixed size memory mapped cache file to store the 'available' information.
This sets the size of that cache (in bytes).
Build-Essential
Defines which package(s) are considered essential build dependencies.
Get
The Get subsection controls the apt-get(8) tool, please see its documentation for more
information about the options here.
Cache
The Cache subsection controls the apt-cache(8) tool, please see its documentation for
more information about the options here.
CDROM
The CDROM subsection controls the apt-cdrom(8) tool, please see its documentation for
more information about the options here.
THE ACQUIRE GROUP
The Acquire group of options controls the download of packages and the URI handlers.
PDiffs
Try do download deltas called PDiffs for Packages or Sources files instead of
downloading whole ones. True by default.
Queue-Mode
Queuing mode; Queue-Mode can be one of host or access which determines how APT
parallelizes outgoing connections. host means that one connection per target host
will be opened, access means that one connection per URI type will be opened.
Retries
Number of retries to perform. If this is non-zero APT will retry failed files the
given number of times.
Source-Symlinks
Use symlinks for source archives. If set to true then source archives will be
symlinked when possible instead of copying. True is the default.
http
HTTP URIs; http::Proxy is the default http proxy to use. It is in the standard form of
http://[[user][:pass]@]host[:port]/. Per host proxies can also be specified by using
the form http::Proxy::<host> with the special keyword DIRECT meaning to use no
proxies. The http_proxy environment variable will override all settings.
Three settings are provided for cache control with HTTP/1.1 compliant proxy caches.
No-Cache tells the proxy to not use its cached response under any circumstances,
Max-Age is sent only for index files and tells the cache to refresh its object if it
is older than the given number of seconds. Debian updates its index files daily so the
default is 1 day. No-Store specifies that the cache should never store this request,
it is only set for archive files. This may be useful to prevent polluting a proxy
cache with very large .deb files. Note: Squid 2.0.2 does not support any of these
options.
The option timeout sets the timeout timer used by the method, this applies to all
things including connection timeout and data timeout.
One setting is provided to control the pipeline depth in cases where the remote server
is not RFC conforming or buggy (such as Squid 2.0.2) Acquire::http::Pipeline-Depth can
be a value from 0 to 5 indicating how many outstanding requests APT should send. A
value of zero MUST be specified if the remote host does not properly linger on TCP
connections - otherwise data corruption will occur. Hosts which require this are in
violation of RFC 2068.
https
HTTPS URIs. Cache-control and proxy options are the same as for http method.
Pipeline-Depth option is not supported yet.
CaInfo suboption specifies place of file that holds info about trusted certificates.
<host>::CaInfo is corresponding per-host option. Verify-Peer boolean suboption
determines whether verify server's host certificate against trusted certificates or
not. <host>::Verify-Peer is corresponding per-host option. Verify-Host boolean
suboption determines whether verify server's hostname or not. <host>::Verify-Host is
corresponding per-host option. SslCert determines what certificate to use for client
authentication. <host>::SslCert is corresponding per-host option. SslKey determines
what private key to use for client authentication. <host>::SslKey is corresponding
per-host option. SslForceVersion overrides default SSL version to use. Can contain
'TLSv1' or 'SSLv3' string. <host>::SslForceVersion is corresponding per-host option.
ftp
FTP URIs; ftp::Proxy is the default proxy server to use. It is in the standard form of
ftp://[[user][:pass]@]host[:port]/ and is overridden by the ftp_proxy environment
variable. To use a ftp proxy you will have to set the ftp::ProxyLogin script in the
configuration file. This entry specifies the commands to send to tell the proxy server
what to connect to. Please see /usr/share/doc/apt/examples/configure-index.gz for an
example of how to do this. The substitution variables available are $(PROXY_USER)
$(PROXY_PASS) $(SITE_USER) $(SITE_PASS) $(SITE) and $(SITE_PORT) Each is taken from
it's respective URI component.
The option timeout sets the timeout timer used by the method, this applies to all
things including connection timeout and data timeout.
Several settings are provided to control passive mode. Generally it is safe to leave
passive mode on, it works in nearly every environment. However some situations require
that passive mode be disabled and port mode ftp used instead. This can be done
globally, for connections that go through a proxy or for a specific host (See the
sample config file for examples).
It is possible to proxy FTP over HTTP by setting the ftp_proxy environment variable to
a http url - see the discussion of the http method above for syntax. You cannot set
this in the configuration file and it is not recommended to use FTP over HTTP due to
its low efficiency.
The setting ForceExtended controls the use of RFC2428 EPSV and EPRT commands. The
default is false, which means these commands are only used if the control connection
is IPv6. Setting this to true forces their use even on IPv4 connections. Note that
most FTP servers do not support RFC2428.
cdrom
CDROM URIs; the only setting for CDROM URIs is the mount point, cdrom::Mount which
must be the mount point for the CDROM drive as specified in /etc/fstab. It is possible
to provide alternate mount and unmount commands if your mount point cannot be listed
in the fstab (such as an SMB mount and old mount packages). The syntax is to put
"/cdrom/"::Mount "foo";
within the cdrom block. It is important to have the trailing slash. Unmount commands
can be specified using UMount.
gpgv
GPGV URIs; the only option for GPGV URIs is the option to pass additional parameters
to gpgv. gpgv::Options Additional options passed to gpgv.
DIRECTORIES
The Dir::State section has directories that pertain to local state information. lists is
the directory to place downloaded package lists in and status is the name of the dpkg
status file. preferences is the name of the APT preferences file. Dir::State contains
the default directory to prefix on all sub items if they do not start with / or ./.
Dir::Cache contains locations pertaining to local cache information, such as the two
package caches srcpkgcache and pkgcache as well as the location to place downloaded
archives, Dir::Cache::archives. Generation of caches can be turned off by setting their
names to be blank. This will slow down startup but save disk space. It is probably
preferred to turn off the pkgcache rather than the srcpkgcache. Like Dir::State the
default directory is contained in Dir::Cache
Dir::Etc contains the location of configuration files, sourcelist gives the location of
the sourcelist and main is the default configuration file (setting has no effect, unless
it is done from the config file specified by APT_CONFIG).
The Dir::Parts setting reads in all the config fragments in lexical order from the
directory specified. After this is done then the main config file is loaded.
Binary programs are pointed to by Dir::Bin. Dir::Bin::Methods specifies the location of
the method handlers and gzip, dpkg, apt-get dpkg-source dpkg-buildpackage and apt-cache
specify the location of the respective programs.
The configuration item RootDir has a special meaning. If set, all paths in Dir:: will be
relative to RootDir, even paths that are specified absolutely. So, for instance, if
RootDir is set to /tmp/staging and Dir::State::status is set to /var/lib/dpkg/status, then
the status file will be looked up in /tmp/staging/var/lib/dpkg/status.
APT IN DSELECT
When APT is used as a dselect(8) method several configuration directives control the
default behaviour. These are in the DSelect section.
Clean
Cache Clean mode; this value may be one of always, prompt, auto, pre-auto and never.
always and prompt will remove all packages from the cache after upgrading, prompt (the
default) does so conditionally. auto removes only those packages which are no longer
downloadable (replaced with a new version for instance). pre-auto performs this action
before downloading new packages.
options
The contents of this variable is passed to apt-get(8) as command line options when it
is run for the install phase.
Updateoptions
The contents of this variable is passed to apt-get(8) as command line options when it
is run for the update phase.
PromptAfterUpdate
If true the [U]pdate operation in dselect(8) will always prompt to continue. The
default is to prompt only on error.
HOW APT CALLS DPKG
Several configuration directives control how APT invokes dpkg(8). These are in the DPkg
section.
options
This is a list of options to pass to dpkg. The options must be specified using the
list notation and each list item is passed as a single argument to dpkg(8).
Pre-Invoke, Post-Invoke
This is a list of shell commands to run before/after invoking dpkg(8). Like options
this must be specified in list notation. The commands are invoked in order using
/bin/sh, should any fail APT will abort.
Pre-Install-Pkgs
This is a list of shell commands to run before invoking dpkg. Like options this must
be specified in list notation. The commands are invoked in order using /bin/sh, should
any fail APT will abort. APT will pass to the commands on standard input the filenames
of all .deb files it is going to install, one per line.
Version 2 of this protocol dumps more information, including the protocol version, the
APT configuration space and the packages, files and versions being changed. Version 2
is enabled by setting DPkg::Tools::options::cmd::Version to 2. cmd is a command given
to Pre-Install-Pkgs.
Run-Directory
APT chdirs to this directory before invoking dpkg, the default is /.
Build-options
These options are passed to dpkg-buildpackage(1) when compiling packages, the default
is to disable signing and produce all binaries.
PERIODIC AND ARCHIVES OPTIONS
APT::Periodic and APT::Archives groups of options configure behavior of apt periodic
updates, which is done by /etc/cron.daily/apt script. See header of this script for the
brief documentation of these options.
DEBUG OPTIONS
Enabling options in the Debug:: section will cause debugging information to be sent to the
standard error stream of the program utilizing the apt libraries, or enable special
program modes that are primarily useful for debugging the behavior of apt. Most of these
options are not interesting to a normal user, but a few may be:
o Debug::pkgProblemResolver enables output about the decisions made by dist-upgrade,
upgrade, install, remove, purge.
o Debug::NoLocking disables all file locking. This can be used to run some operations
(for instance, apt-get -s install) as a non-root user.
o Debug::pkgDPkgPM prints out the actual command line each time that apt invokes
dpkg(8).
o Debug::IdentCdrom disables the inclusion of statfs data in CDROM IDs.
A full list of debugging options to apt follows.
Debug::Acquire::cdrom
Print information related to accessing cdrom:// sources.
Debug::Acquire::ftp
Print information related to downloading packages using FTP.
Debug::Acquire::http
Print information related to downloading packages using HTTP.
Debug::Acquire::https
Print information related to downloading packages using HTTPS.
Debug::Acquire::gpgv
Print information related to verifying cryptographic signatures using gpg.
Debug::aptcdrom
Output information about the process of accessing collections of packages stored on
CD-ROMs.
Debug::BuildDeps
Describes the process of resolving build-dependencies in apt-get(8).
Debug::Hashes
Output each cryptographic hash that is generated by the apt libraries.
Debug::IdentCDROM
Do not include information from statfs, namely the number of used and free blocks on
the CD-ROM filesystem, when generating an ID for a CD-ROM.
Debug::NoLocking
Disable all file locking. For instance, this will allow two instances of "apt-get
update" to run at the same time.
Debug::pkgAcquire
Log when items are added to or removed from the global download queue.
Debug::pkgAcquire::Auth
Output status messages and errors related to verifying checksums and cryptographic
signatures of downloaded files.
Debug::pkgAcquire::Diffs
Output information about downloading and applying package index list diffs, and errors
relating to package index list diffs.
Debug::pkgAcquire::RRed
Output information related to patching apt package lists when downloading index diffs
instead of full indices.
Debug::pkgAcquire::Worker
Log all interactions with the sub-processes that actually perform downloads.
Debug::pkgAutoRemove
Log events related to the automatically-installed status of packages and to the
removal of unused packages.
Debug::pkgDepCache::AutoInstall
Generate debug messages describing which packages are being automatically installed to
resolve dependencies. This corresponds to the initial auto-install pass performed in,
e.g., apt-get install, and not to the full apt dependency resolver; see
Debug::pkgProblemResolver for that.
Debug::pkgInitConfig
Dump the default configuration to standard output on startup.
Debug::pkgDPkgPM
When invoking dpkg(8), output the precise command line with which it is being invoked,
with arguments separated by a single space character.
Debug::pkgDPkgProgressReporting
Output all the data received from dpkg(8) on the status file descriptor and any errors
encountered while parsing it.
Debug::pkgOrderList
Generate a trace of the algorithm that decides the order in which apt should pass
packages to dpkg(8).
Debug::pkgPackageManager
Output status messages tracing the steps performed when invoking dpkg(8).
Debug::pkgPolicy
Output the priority of each package list on startup.
Debug::pkgProblemResolver
Trace the execution of the dependency resolver (this applies only to what happens when
a complex dependency problem is encountered).
Debug::sourceList
Print information about the vendors read from /etc/apt/vendors.list.
Debug::Vendor
Print information about each vendor.
EXAMPLES
/usr/share/doc/apt/examples/configure-index.gz is a configuration file showing example
values for all possible options.
FILES
/etc/apt/apt.conf
SEE ALSO
apt-cache(8), apt-config(8), apt_preferences(5).
BUGS
APT bug page[1]. If you wish to report a bug in APT, please see
/usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.
AUTHORS
Jason Gunthorpe
Author.
APT team
Author.
Daniel Burrows <dburrows AT debian.org>
Initial documentation of Debug::*.
NOTES
1. APT bug page
http://bugs.debian.org/src:apt
Linux 10 December 2008 APT.CONF(5)
Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2012-05-25 17:27 @38.107.179.237 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)