6.9. Searching for Packages
With the large and ever-growing amount of software in Debian, there emerges a paradox: Debian usually has a tool for most tasks, but that tool can be very difficult to find amongst the myriad other packages. The lack of appropriate ways to search for (and to find) the right tool has long been a problem. Fortunately, this problem has almost entirely been solved.
The most trivial search possible is looking up an exact package name. If apt show package
returns a result, then the package exists. Unfortunately, this requires knowing or even guessing the package name, which isn't always possible.
A slightly more successful searching pattern is a plain-text search in package names, but it remains very limited. You can generally find results by searching package descriptions: since each package has a more or less detailed description in addition to its package name, a keyword search in these descriptions will often be useful. apt-cache
and axi-cache
are the tools of choice for this kind of search; for instance, apt-cache search video
will return a list of all packages whose name or description contains the keyword “video”.
For more complex searches, a more powerful tool such as aptitude
is required. aptitude
allows you to search according to a logical expression based on the package's meta-data fields. For instance, the following command searches for packages whose name contains kino
, whose description contains video
and whose maintainer's name contains paul
:
$ aptitude search kino~dvideo~mpaul
p kino - Non-linear editor for Digital Video data
$ aptitude show kino
Package: kino
State: not installed
Version: 1.3.4-2.1+b1
Priority: extra
Section: video
Maintainer: Paul Brossier <piem@debian.org>
Architecture: amd64
Uncompressed Size: 8,472 k
Depends: libasound2 (>= 1.0.16), libatk1.0-0 (>= 1.12.4), libavc1394-0 (>=
0.5.3), libavcodec56 (>= 6:11~beta1) | libavcodec-extra-56 (>=
6:11~beta1), libavformat56 (>= 6:11~beta1), libavutil54 (>=
6:11~beta1), libc6 (>= 2.14), libcairo2 (>= 1.2.4), libdv4,
libfontconfig1 (>= 2.11), libfreetype6 (>= 2.2.1), libgcc1 (>=
1:4.1.1), libgdk-pixbuf2.0-0 (>= 2.22.0), libglade2-0 (>= 1:2.6.4-2~),
libglib2.0-0 (>= 2.12.0), libgtk2.0-0 (>= 2.24.0), libice6 (>=
1:1.0.0), libiec61883-0 (>= 1.2.0), libpango-1.0-0 (>= 1.14.0),
libpangocairo-1.0-0 (>= 1.14.0), libpangoft2-1.0-0 (>= 1.14.0),
libquicktime2 (>= 2:1.2.2), libraw1394-11, libsamplerate0 (>= 0.1.7),
libsm6, libstdc++6 (>= 4.9), libswscale3 (>= 6:11~beta1), libx11-6,
libxext6, libxml2 (>= 2.7.4), libxv1, zlib1g (>= 1:1.1.4)
Recommends: ffmpeg, curl
Suggests: udev | hotplug, vorbis-tools, sox, mjpegtools, lame, ffmpeg2theora
Conflicts: kino-dvtitler, kino-timfx, kinoplus
Replaces: kino-dvtitler, kino-timfx, kinoplus
Provides: kino-dvtitler, kino-timfx, kinoplus
Description: Non-linear editor for Digital Video data
Kino allows you to record, create, edit, and play movies recorded with DV
camcorders. This program uses many keyboard commands for fast navigating and
editing inside the movie.
The kino-timfx, kino-dvtitler and kinoplus sets of plugins, formerly
distributed as separate packages, are now provided with Kino.
Homepage: http://www.kinodv.org/
Tags: field::arts, hardware::camera, implemented-in::c, implemented-in::c++,
interface::x11, role::program, scope::application, suite::gnome,
uitoolkit::gtk, use::editing, use::learning, works-with::video,
x11::application
The search only returns one package, kino, which satisfies all three criteria.
Even these multi-criteria searches are rather unwieldy, which explains why they are not used as much as they could. A new tagging system has therefore been developed, and it provides a new approach to searching. Packages are given tags that provide a thematical classification along several strands, known as a “facet-based classification”. In the case of kino above, the package's tags indicate that Kino is a Gnome-based software that works on video data and whose main purpose is editing.
Browsing this classification can help you to search for a package which corresponds to known needs; even if it returns a (moderate) number of hits, the rest of the search can be done manually. To do that, you can use the
~G
search pattern in
aptitude
, but it is probably easier to simply navigate the site where tags are managed:
Selecting the works-with::video
and use::editing
tags yields a handful of packages, including the kino and pitivi video editors. This system of classification is bound to be used more and more as time goes on, and package managers will gradually provide efficient search interfaces based on it.
总的来说,最好的工具取决于搜索时你所期望达到的复杂程度:
apt-cache
只能通过软件包名称和描述信息来进行搜索,对于搜索符合少量关键词的特定软件包十分方便;
当搜索条件包括软件包之间的关系或者像维护者名称的其它元数据时,synaptic
将更加有用;
当需要基于标签来搜索时,packagesearch
是一个很好用的工具,可以根据若干条件(包括软件包中包含的文件名)进行软件包搜索的图形化专用工具。命令行下则使用 axi-cache
。
最后,当搜索涉及有逻辑操作的复杂的表达式时,首选工具为 aptitude
的搜索语法,尽管有点晦涩难用但功能相当强大,它有命令行和交互两种模式。