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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: