* Manual fixes.

This commit is contained in:
Eelco Dolstra 2004-11-14 00:24:57 +00:00
parent 54c7a870d5
commit 0b79a12082
3 changed files with 50 additions and 51 deletions

View file

@ -12,11 +12,11 @@ features are:
<itemizedlist> <itemizedlist>
<listitem><para>It makes sure that dependency specifications are <listitem><para>It helps you make sure that dependency specifications
complete. In general in a deployment system you have to specify for are complete. In general in a deployment system you have to specify
each component what its dependencies are, but there are no guarantees for each component what its dependencies are, but there are no
that this specification is complete. If you forget a dependency, then guarantees that this specification is complete. If you forget a
the component will build and work correctly on dependency, then the component will build and work correctly on
<emphasis>your</emphasis> machine if you have the dependency <emphasis>your</emphasis> machine if you have the dependency
installed, but not on the end user's machine if it's not installed, but not on the end user's machine if it's not
there.</para></listitem> there.</para></listitem>
@ -25,8 +25,8 @@ there.</para></listitem>
variants</emphasis> of a component installed at the same time. In variants</emphasis> of a component installed at the same time. In
contrast, in systems such as RPM different versions of the same contrast, in systems such as RPM different versions of the same
package tend to install to the same location in the file system, so package tend to install to the same location in the file system, so
you installing one version will remove the other. This is especially installing one version will remove the other. This is especially
important if you want to have use applications that have conflicting important if you want to use applications that have conflicting
requirements on different versions of a component (e.g., application A requirements on different versions of a component (e.g., application A
requires version 1.0 of library X, while application B requires a requires version 1.0 of library X, while application B requires a
non-backwards compatible version 1.1).</para></listitem> non-backwards compatible version 1.1).</para></listitem>
@ -45,24 +45,23 @@ component to fail).</para></listitem>
<listitem><para>Likewise, it is possible to atomically roll back after <listitem><para>Likewise, it is possible to atomically roll back after
an install, upgrade, or uninstall action. That is, in a fast (O(1)) an install, upgrade, or uninstall action. That is, in a fast (O(1))
operation the previous configuration of the system will be restored. operation the previous configuration of the system can be restored.
This is because upgrade or uninstall actions doesn't actually remove This is because upgrade or uninstall actions don't actually remove
components from the system.</para></listitem> components from the system.</para></listitem>
<listitem><para>Unused components can be <listitem><para>Unused components can be
<emphasis>garbage-collected</emphasis> automatically and safely. <emphasis>garbage-collected</emphasis> automatically and safely: when
I.e., when you remove an application from a profile, its dependencies you remove an application from a profile, its dependencies will be
will be deleted by the garbage collector if there are no other active deleted by the garbage collector only if there are no other active
applications that are using it.</para></listitem> applications using them.</para></listitem>
<listitem><para>Nix supports both source-based deployment models <listitem><para>Nix supports both source-based deployment models
(where you distribute <emphasis>Nix expressions</emphasis> that tell (where you distribute <emphasis>Nix expressions</emphasis> that tell
Nix how to build software from source) and binary-based deployment Nix how to build software from source) and binary-based deployment
models. The latter is more-or-less transparent: installation of models. The latter is more-or-less transparent: installation of
components is always based on Nix expressions, but if those components is always based on Nix expressions, but if the expressions
expressions have been built before and Nix knows that the resulting have been built before and Nix knows that the resulting binaries are
binaries are available somewhere, it will use those available somewhere, it will use those instead.</para></listitem>
instead.</para></listitem>
<listitem><para>Nix is flexible in the deployment policies that it <listitem><para>Nix is flexible in the deployment policies that it
supports. There is a clear separation between the tools that supports. There is a clear separation between the tools that
@ -80,13 +79,12 @@ This means that if a component was built succesfully once, it can be
rebuilt again on another machine and the result will be the same. We rebuilt again on another machine and the result will be the same. We
cannot <emphasis>guarantee</emphasis> this (e.g., if the build depends cannot <emphasis>guarantee</emphasis> this (e.g., if the build depends
on the time-of-day), but Nix (and the tools in the Nix Packages on the time-of-day), but Nix (and the tools in the Nix Packages
collection) takes special measures to help achieve collection) takes special care to help achieve this.</para></listitem>
this.</para></listitem>
<listitem><para>Nix expressions (the things that tell Nix how to build <listitem><para>Nix expressions (the things that tell Nix how to build
components) are self-contained: they describe not just components but components) are self-contained: they describe not just components but
complete compositions. In other words, Nix expressions also describe complete compositions. In other words, Nix expressions also describe
how to build all the dependencies. This is contrast to component how to build all the dependencies. This is in contrast to component
specification languages like RPM spec files, which might say that a specification languages like RPM spec files, which might say that a
component X depends on some other component Y, but since it does not component X depends on some other component Y, but since it does not
describe <emphasis>exactly</emphasis> what Y is, the result of describe <emphasis>exactly</emphasis> what Y is, the result of
@ -111,7 +109,7 @@ platforms.</para></listitem>
also for <emphasis>service deployment</emphasis>, such as the also for <emphasis>service deployment</emphasis>, such as the
deployment of a complete web server with all its configuration files, deployment of a complete web server with all its configuration files,
static pages, software dependencies, and so on. Nix's advantages for static pages, software dependencies, and so on. Nix's advantages for
software deployment also apply here, for instance, the ability software deployment also apply here: for instance, the ability
trivially to have multiple configurations at the same time, or the trivially to have multiple configurations at the same time, or the
ability to do rollbacks.</para></listitem> ability to do rollbacks.</para></listitem>

View file

@ -31,7 +31,7 @@ Nix expressions called the Nix Package collection that contains
components ranging from basic development stuff such as GCC and Glibc, components ranging from basic development stuff such as GCC and Glibc,
to end-user applications like Mozilla Firefox. (Nix is however not to end-user applications like Mozilla Firefox. (Nix is however not
tied to the Nix Package collection; you could write your own Nix tied to the Nix Package collection; you could write your own Nix
expression based on that, or completely new.) You can download the expression based on it, or completely new ones.) You can download the
latest version from <ulink latest version from <ulink
url='http://catamaran.labs.cs.uu.nl/dist/nix' />. You probably want url='http://catamaran.labs.cs.uu.nl/dist/nix' />. You probably want
the latest unstable release; currently the stable releases tend to lag the latest unstable release; currently the stable releases tend to lag
@ -55,7 +55,7 @@ where <literal>nixpkgs-<replaceable>version</replaceable></literal> is
where you've unpacked the release.</para> where you've unpacked the release.</para>
<para>It is also possible to see the <emphasis>status</emphasis> of <para>It is also possible to see the <emphasis>status</emphasis> of
available component, i.e., whether they are installed into the user available components, i.e., whether they are installed into the user
environment and/or present in the system: environment and/or present in the system:
<screen> <screen>
@ -69,12 +69,13 @@ IPS bison-1.875d
The first character (<literal>I</literal>) indicates whether the The first character (<literal>I</literal>) indicates whether the
component is installed in your current user environment. The second component is installed in your current user environment. The second
(<literal>P</literal>) indicates whether it is present on your system (<literal>P</literal>) indicates whether it is present on your system
(in which case installing it into your user environment would be very (in which case installing it into your user environment would be a
quick). The last one (<literal>S</literal>) indicates whether there very quick operation). The last one (<literal>S</literal>) indicates
is a so-called <emphasis>substitute</emphasis> for the component, whether there is a so-called <emphasis>substitute</emphasis> for the
which is Nix's mechanism for doing binary deployment. It just means component, which is Nix's mechanism for doing binary deployment. It
that Nix know that it can fetch a pre-built component from somewhere just means that Nix know that it can fetch a pre-built component from
(typically a network server) instead of building it locally.</para> somewhere (typically a network server) instead of building it
locally.</para>
<para>So now that we have a set of Nix expressions we can build the <para>So now that we have a set of Nix expressions we can build the
components contained in them. This is done using <literal>nix-env components contained in them. This is done using <literal>nix-env
@ -91,8 +92,8 @@ system</ulink>).</para>
<para>When you do this for the first time, Nix will start building <para>When you do this for the first time, Nix will start building
Subversion and all its dependencies. This will take quite a while — Subversion and all its dependencies. This will take quite a while —
typically an hour or two on modern machines. Fortunately, there is a typically an hour or two on modern machines. Fortunately, there is a
faster way (so just do a Ctrl-C on that install operation!): you just faster way (so do a Ctrl-C on that install operation!): you just need
need to tell Nix that pre-built binaries of all those components are to tell Nix that pre-built binaries of all those components are
available somewhere. This is done using the available somewhere. This is done using the
<command>nix-pull</command> command, which must be supplied with a URL <command>nix-pull</command> command, which must be supplied with a URL
containing a <emphasis>manifest</emphasis> describing what binaries containing a <emphasis>manifest</emphasis> describing what binaries
@ -110,7 +111,7 @@ downloading binaries from <systemitem
class='fqdomainname'>catamaran.labs.cs.uu.nl</systemitem>, instead of class='fqdomainname'>catamaran.labs.cs.uu.nl</systemitem>, instead of
building them from source. This might still take a while since all building them from source. This might still take a while since all
dependencies must be downloaded, but on a reasonably fast connection dependencies must be downloaded, but on a reasonably fast connection
such as an ADSL line it's on the order of a few minutes.</para> such as an DSL line it's on the order of a few minutes.</para>
<para>Naturally, packages can also be uninstalled: <para>Naturally, packages can also be uninstalled:
@ -127,10 +128,10 @@ $ nix-env -f nixpkgs-<replaceable>version</replaceable> -u subversion</screen>
This will <emphasis>only</emphasis> upgrade Subversion if there is a This will <emphasis>only</emphasis> upgrade Subversion if there is a
<quote>newer</quote> version in the new set of Nix expressions, as <quote>newer</quote> version in the new set of Nix expressions, as
defined by some pretty much arbitrary rules regarding ordering of defined by some pretty arbitrary rules regarding ordering of version
version numbers (which generally do what you'd expect of them). To numbers (which generally do what you'd expect of them). To just
just unconditionally replace Subversion with whatever version is in unconditionally replace Subversion with whatever version is in the Nix
the Nix expressions, use <parameter>-i</parameter> instead of expressions, use <parameter>-i</parameter> instead of
<parameter>-u</parameter>; <parameter>-i</parameter> will remove <parameter>-u</parameter>; <parameter>-i</parameter> will remove
whatever version is already installed.</para> whatever version is already installed.</para>
@ -261,7 +262,7 @@ lrwxrwxrwx 1 eelco ... default-43-link -> /nix/store/84c85f89ddbf...-user-env
lrwxrwxrwx 1 eelco ... default -> default-43-link</screen> lrwxrwxrwx 1 eelco ... default -> default-43-link</screen>
This shows a profile called <filename>default</filename>. The file This shows a profile called <filename>default</filename>. The file
<filename>default</filename> itself is actually a symlink that point <filename>default</filename> itself is actually a symlink that points
to the current generation. When we do a <command>nix-env</command> to the current generation. When we do a <command>nix-env</command>
operation, a new user environment and generation link are created operation, a new user environment and generation link are created
based on the current one, and finally the <filename>default</filename> based on the current one, and finally the <filename>default</filename>
@ -295,13 +296,13 @@ $ nix-env --list-generations</screen></para>
figure above. You generally wouldn't have figure above. You generally wouldn't have
<filename>/nix/var/nix/profiles/<replaceable>some-profile</replaceable>/bin</filename> <filename>/nix/var/nix/profiles/<replaceable>some-profile</replaceable>/bin</filename>
in your <envar>PATH</envar>. Rather, there is a symlink in your <envar>PATH</envar>. Rather, there is a symlink
<filename>~/.nix-profile</filename> that point to your current <filename>~/.nix-profile</filename> that points to your current
profile. This means that you should put profile. This means that you should put
<filename>~/.nix-profile/bin</filename> in your <envar>PATH</envar> <filename>~/.nix-profile/bin</filename> in your <envar>PATH</envar>
(and indeed, that's what the initialisation script (and indeed, that's what the initialisation script
<filename>/nix/etc/profile.d/nix.sh</filename> does). This makes it <filename>/nix/etc/profile.d/nix.sh</filename> does). This makes it
easier to switch to a different profile, which is exactly what the easier to switch to a different profile. You can do that using the
command <command>nix-env --switch-profile</command> does: command <command>nix-env --switch-profile</command>:
<screen> <screen>
$ nix-env --switch-profile /nix/var/nix/profiles/my-profile $ nix-env --switch-profile /nix/var/nix/profiles/my-profile
@ -311,14 +312,14 @@ $ nix-env --switch-profile /nix/var/nix/profiles/default</screen>
These commands switch to the <filename>my-profile</filename> and These commands switch to the <filename>my-profile</filename> and
default profile, respectively. If the profile doesn't exist, it will default profile, respectively. If the profile doesn't exist, it will
be created automatically. You should be careful about storing a be created automatically. You should be careful about storing a
profile in another location that the <filename>profiles</filename> profile in another location than the <filename>profiles</filename>
directory, since otherwise it might not be used as a root to the directory, since otherwise it might not be used as a root of the
garbage collection (see section <xref linkend='sec-garbage-collection' garbage collector (see section <xref linkend='sec-garbage-collection'
/>).</para> />).</para>
<para>All <command>nix-env</command> operations work on the profile <para>All <command>nix-env</command> operations work on the profile
pointed to by <command>~/.nix-profile</command>, but you can override pointed to by <command>~/.nix-profile</command>, but you can override
this on using the <option>--profile</option> option (abbreviation this using the <option>--profile</option> option (abbreviation
<option>-p</option>): <option>-p</option>):
<screen> <screen>
@ -335,7 +336,7 @@ This will <emphasis>not</emphasis> change the
<para><command>nix-env</command> operations such as upgrades <para><command>nix-env</command> operations such as upgrades
(<option>-u</option>) and uninstall (<option>-e</option>) never (<option>-u</option>) and uninstall (<option>-e</option>) never
actually delete components from the system. All they do (as shown actually delete components from the system. All they do (as shown
above) is to make a new user environment that no longer contains above) is to create a new user environment that no longer contains
symlinks to the <quote>deleted</quote> components.</para> symlinks to the <quote>deleted</quote> components.</para>
<para>Of course, since disk space is not infinite, unused components <para>Of course, since disk space is not infinite, unused components
@ -414,10 +415,10 @@ a set of Nix expressions and a manifest. Using the command
with whatever is available at that URL.</para> with whatever is available at that URL.</para>
<para>You can <quote>subscribe</quote> to a channel using <para>You can <quote>subscribe</quote> to a channel using
<command>nix-channel --subscribe</command>, e.g., <command>nix-channel --add</command>, e.g.,
<screen> <screen>
$ nix-channel --subscribe http://catamaran.labs.cs.uu.nl/dist/nix/channels/nixpkgs-unstable</screen> $ nix-channel --add http://catamaran.labs.cs.uu.nl/dist/nix/channels/nixpkgs-unstable</screen>
subscribes you to a channel that always contains that latest version subscribes you to a channel that always contains that latest version
of the Nix Packages collection. (Instead of of the Nix Packages collection. (Instead of
@ -446,9 +447,9 @@ makes the union of each channel's Nix expressions the default for
$ nix-env -u '*'</screen> $ nix-env -u '*'</screen>
to upgrade all components in your profile to the latest versions to upgrade all components in your profile to the latest versions
available in the channels.</para> available in the subscribed channels.</para>
</sect1> </sect1>
</chapter> </chapter>

View file

@ -102,7 +102,7 @@ $ nix-env --rollback</screen>
<listitem><para>You should periodically run the Nix garbage collector <listitem><para>You should periodically run the Nix garbage collector
to get rid of unused packages, since uninstalls or upgrades don't to get rid of unused packages, since uninstalls or upgrades don't
actual delete them: actually delete them:
<screen> <screen>
$ nix-env --delete-generations old $ nix-env --delete-generations old
@ -115,4 +115,4 @@ second command actually deletes them.</para></listitem>
</orderedlist> </orderedlist>
</chapter> </chapter>