between <literal>/*</literal> and <literal>*/</literal>, just like C/C++ comments.
Each line is of the form
<literal>APT::Get::Assume-Yes "true";</literal> The trailing
- semicolon is required and the quotes are optional. A new scope can be
- opened with curly braces, like:</para>
+ semicolon and the quotes are required. The value must be on one line, and
+ there is no kind of string concatenation. It must not include inside quotes.
+ The behavior of the backslash "\" and escaped characters inside a value is
+ undefined and it should not be used. An option name may include
+ alphanumerical characters and the "/-:._+" characters. A new scope can
+ be opened with curly braces, like:</para>
<informalexample><programlisting>
APT {
<para>The names of the configuration items are not case-sensitive. So in the previous example
you could use <literal>dpkg::pre-install-pkgs</literal>.</para>
- <para>Two specials are allowed, <literal>#include</literal> and <literal>#clear</literal>
+ <para>Names for the configuration items are optional if a list is defined as it can be see in
+ the <literal>DPkg::Pre-Install-Pkgs</literal> example above. If you don't specify a name a
+ new entry will simply add a new option to the list. If you specify a name you can override
+ the option as every other option by reassigning a new value to the option.</para>
+
+ <para>Two specials are allowed, <literal>#include</literal> (which is deprecated
+ and not supported by alternative implementations) and <literal>#clear</literal>:
<literal>#include</literal> will include the given file, unless the filename
ends in a slash, then the whole directory is included.
<literal>#clear</literal> is used to erase a part of the configuration tree. The
- specified element and all its descendants are erased.</para>
+ specified element and all its descendants are erased.
+ (Note that these lines also need to end with a semicolon.)</para>
+
+ <para>The #clear command is the only way to delete a list or a complete scope.
+ Reopening a scope or the ::-style described below will <emphasis>not</emphasis>
+ override previously written entries. Only options can be overridden by addressing a new
+ value to it - lists and scopes can't be overridden, only cleared.</para>
<para>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 (<literal>APT::Get::Assume-Yes</literal> 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.</para>
+ a trailing :: to the list name. (As you might suspect: The scope syntax can't be used
+ on the command line.)</para>
+
+ <para>Note that you can use :: only for appending one item per line to a list and
+ that you should not use it in combination with the scope syntax.
+ (The scope syntax implicit insert ::) Using both syntaxes together will trigger a bug
+ which some users unfortunately relay on: An option with the unusual name "<literal>::</literal>"
+ which acts like every other option with a name. These introduces many problems
+ including that a user who writes multiple lines in this <emphasis>wrong</emphasis> syntax in
+ the hope to append to a list will gain the opposite as only the last assignment for this option
+ "<literal>::</literal>" will be used. Upcoming APT versions will raise errors and
+ will stop working if they encounter this misuse, so please correct such statements now
+ as long as APT doesn't complain explicit about them.</para>
</refsect1>
<refsect1><title>The APT Group</title>
</varlistentry>
<varlistentry><term>Immediate-Configure</term>
- <listitem><para>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.</para></listitem>
+ <listitem><para>Defaults to on which will cause APT to install essential and important packages
+ as fast as possible in the install/upgrade operation. This is done to limit the effect of a failing
+ &dpkg; call: If this option is disabled APT doesn't treat an important package in the same way as
+ an extra package: Between the unpacking of the important package A and his configuration can then
+ be many other unpack or configuration calls, e.g. for package B which has no relation to A, but
+ causes the dpkg call to fail (e.g. because maintainer script of package B generates an error) which results
+ in a system state in which package A is unpacked but unconfigured - each package depending on A is now no
+ longer guaranteed to work as their dependency on A is not longer satisfied. The immediate configuration marker
+ is also applied to all dependencies which can generate a problem if the dependencies e.g. form a circle
+ as a dependency with the immediate flag is comparable with a Pre-Dependency. So in theory it is possible
+ that APT encounters a situation in which it is unable to perform immediate configuration, error out and
+ refers to this option so the user can deactivate the immediate configuration temporary to be able to perform
+ an install/upgrade again. Note the use of the word "theory" here as this problem was only encountered by now
+ in real world a few times in non-stable distribution versions and caused by wrong dependencies of the package
+ in question, so you should not blindly disable this option as the mentioned scenario above is not the only
+ problem immediate configuration can help to prevent in the first place.</para></listitem>
</varlistentry>
<varlistentry><term>Force-LoopBreak</term>
<para>The used bandwidth can be limited with <literal>Acquire::http::Dl-Limit</literal>
which accepts integer values in kilobyte. The default value is 0 which deactivates
- the limit and tries uses as much as possible of the bandwith (Note that this option implicit
+ the limit and tries uses as much as possible of the bandwidth (Note that this option implicit
deactivates the download from multiple servers at the same time.)</para></listitem>
</varlistentry>
as specified in <filename>/etc/fstab</filename>. 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 <literallayout>"/cdrom/"::Mount "foo";</literallayout> within
+ is to put <literallayout>/cdrom/::Mount "foo";</literallayout> within
the cdrom block. It is important to have the trailing slash. Unmount
commands can be specified using UMount.</para></listitem>
</varlistentry>
<para>Note that at run time the <literal>Dir::Bin::<replaceable>Methodname</replaceable></literal> will
be checked: If this setting exists the method will only be used if this file exists, e.g. for
the bzip2 method (the inbuilt) setting is <literallayout>Dir::Bin::bzip2 "/bin/bzip2";</literallayout>
- Note also that list entries specified on the commandline will be added at the end of the list
+ Note also that list entries specified on the command line will be added at the end of the list
specified in the configuration files, but before the default entries. To prefer a type in this case
over the ones specified in in the configuration files you can set the option direct - not in list style.
This will not override the defined list, it will only prefix the list with this type.</para>
multiply calls of dpkg. Without further options dpkg will use triggers only in between his
own run. Activating these options can therefore decrease the time needed to perform the
install / upgrade. Note that it is intended to activate these options per default in the
- future, but as it changes the way APT calling dpkg drastical it needs a lot more testing.
+ future, but as it changes the way APT calling dpkg drastically it needs a lot more testing.
<emphasis>These options are therefore currently experimental and should not be used in
productive environments.</emphasis> Also it breaks the progress reporting so all frontends will
currently stay around half (or more) of the time in the 100% state while it actually configures
all packages.</para>
- <para>Note that it is not garanteed that APT will support these options or that these options will
+ <para>Note that it is not guaranteed that APT will support these options or that these options will
not cause (big) trouble in the future. If you have understand the current risks and problems with
these options, but are brave enough to help testing them create a new configuration file and test a
combination of options. Please report any bugs, problems and improvements you encounter and make sure
<varlistentry><term>PackageManager::UnpackAll</term>
<listitem><para>As the configuration can be deferred to be done at the end by dpkg it can be
tried to order the unpack series only by critical needs, e.g. by Pre-Depends. Default is true
- and therefore the "old" method of ordering in verious steps by everything. While both method
+ and therefore the "old" method of ordering in various steps by everything. While both method
were present in earlier APT versions the <literal>OrderCritical</literal> method was unused, so
this method is very experimental and needs further improvements before becoming really useful.
</para></listitem>
after unpacking. It will be a good idea to do this quite early in the upgrade process as these
these configure calls require currently also <literal>DPkg::TriggersPending</literal> which
will run quite a few triggers (which maybe not needed). Essentials get per default a high score
- but the immediate flag is relativly low (a package which has a Pre-Depends is higher rated).
+ but the immediate flag is relatively low (a package which has a Pre-Depends is higher rated).
These option and the others in the same group can be used to change the scoring. The following
example shows the settings with there default values.
<literallayout>OrderList::Score {
projects / apt.git / blobdiff