当我执行时dnf search emacs，输出似乎是按行长度排序的（见下文）。
为什么？
[dhc-user@server1 timestudy]$ dnf search emacs
Last metadata expiration check: 2 days, 8:25:38 ago on Sun May 1 17:14:42 2016.
===================================================== N/S Matched: emacs =====================================================
emacs.x86_64 : GNU Emacs text editor
emacs-vm.x86_64 : Emacs VM mail reader
ucblogo-emacs.x86_64 : Emacs Logo mode
emacs-common.x86_64 : Emacs common files
emacspeak.x86_64 : Emacs Speech interface
ocaml-emacs.x86_64 : Emacs mode for OCaml
emacs-pydb.noarch : Pydb support for Emacs
xemacs.i686 : Different version of Emacs
xemacs.x86_64 : Different version of Emacs
emacs-ledger.x86_64 : Emacs mode for ledger
emacs-apel.noarch : A Portable Emacs Library
emacs-mew.x86_64 : Email client for GNU Emacs
emacs-sdcc.x86_64 : Emacs extensions for SDCC
emacs-cdargs.noarch : Cdargs support for Emacs
emacs-irsim-mode.noarch : Irsim mode for emacs
migemo-emacs.noarch : Emacs front-end of Migemo
emacs-lua.noarch : Lua major mode for GNU Emacs
Singular-emacs.x86_64 : Emacs mode for Singular
cvc3-emacs.noarch : Compiled Emacs mode for CVC3
emacs-filesystem.noarch : Emacs filesystem layout
emacs-color-theme.noarch : Color themes for Emacs
emacs-pyrex.noarch : Pyrex editing mode for Emacs
migemo-xemacs.noarch : XEmacs front-end of Migemo
emacs-evil.noarch : Extensible vi layer for Emacs
emacs-notmuch.noarch : Not much support for Emacs
cvc3-xemacs.noarch : Compiled XEmacs mode for CVC3
emacs-global.noarch : GNU GLOBAL support for Emacs
emacs-spice-mode.noarch : SPICE Mode for GNU Emacs
emacs-verilog-mode.noarch : Verilog mode for Emacs
xemacs-devel.i686 : Development files for XEmacs
xemacs-devel.x86_64 : Development files for XEmacs
emacs-auctex.noarch : Enhanced TeX modes for Emacs
emacs-common-w3m.noarch : W3m interface for Emacsen
xemacs-filesystem.noarch : XEmacs filesystem layout
emacs-goodies.noarch : Miscellaneous add on for Emacs
mona-emacs.noarch : Emacs mode for editing Mona files
xemacs-el.x86_64 : Emacs lisp source files for XEmacs
why3-emacs.noarch : Emacs support file for why3 files
gcl-emacs.noarch : Emacs mode for interacting with GCL
undertaker-emacs.noarch : Emacs support for undertaker
emacs-ledger-el.noarch : Emacs elisp source for ledger
mona-xemacs.noarch : XEmacs mode for editing Mona files
why3-xemacs.noarch : XEmacs support file for why3 files
emacs-rinari.noarch : Ruby on rails minor mode for Emacs
gcl-xemacs.noarch : XEmacs mode for interacting with GCL
undertaker-xemacs.noarch : XEmacs support for undertaker
emacs-gnu-smalltalk.noarch : Emacs mode for GNU Smalltalk
why3-emacs-el.noarch : Emacs source file for why3 support
xemacs-pysmell.noarch : Python automcompletion for XEmacs
frama-c-emacs.noarch : Emacs support file for ACSL markup
emacs-haskell-mode.noarch : Haskell editing mode for Emacs
emacs-nox.x86_64 : GNU Emacs text editor without X support
emacs-slime-el.noarch : Elisp source files for emacs-slime
emacs-pysmell.noarch : Python automcompletion for GNU Emacs
frama-c-emacs-el.noarch : Emacs source file for ACSL markup
why3-xemacs-el.noarch : XEmacs source file for why3 support
xemacs-packages-base.noarch : Base lisp packages for XEmacs
frama-c-xemacs.noarch : XEmacs support file for ACSL markup
emacs-pymacs.noarch : Emacs and Python integration framework
emacs-rinari-el.noarch : Elisp source files for emacs-rinari
frama-c-xemacs-el.noarch : XEmacs source file for ACSL markup
clips-emacs.noarch : EMACS add-ons for the CLIPS expert system
emacs-goodies-el.noarch : Elisp source files for Emacs-goodies
emacs-ess-doc.noarch : Documentation of Emacs Speaks Statistics
xemacs-info.noarch : XEmacs documentation in GNU texinfo format
emacs-mmm-el.noarch : Elisp source files for mmm under GNU Emacs
xemacs-ebib-el.noarch : Elisp source files for Ebib under XEmacs
emacs-yaml-mode.noarch : Major mode to edit YAML files for emacs
cvc3-emacs-el.noarch : Elisp source files for the CVC3 Emacs mode
xemacs-packages-extra.noarch : Collection of XEmacs lisp packages
emacs-php-mode.noarch : Major GNU Emacs mode for editing PHP code
emacs-slime.noarch : The superior lisp interaction mode for emacs
emacs-ebib-el.noarch : Elisp source files for Ebib under GNU Emacs
emacs-nesc-el.noarch : Elisp source files for nesC under GNU Emacs
xemacs-ebib.noarch : Compiled elisp files to run Ebib under XEmacs
pinentry-emacs.x86_64 : Passphrase/PIN entry dialog based on emacs
cvc3-xemacs-el.noarch : Elisp source files for the CVC3 XEmacs mode
emacs-bbdb.noarch : A contact management utility for use with Emacs
emacs-htmlize-el.noarch : Emacs Lisp source files for emacs-htmlize
emacs-terminal.noarch : A desktop menu item for GNU Emacs terminal.
coq-emacs.noarch : GNU Emacs support for Coq proof management system
emacs-common-tuareg.noarch : Emacs and XEmacs mode for editing ocaml
emacs-ebib.noarch : Compiled elisp files to run Ebib under GNU Emacs
emacs-magit-el.noarch : Elisp source files for Magit under GNU Emacs
emacs-nesc.noarch : Compiled elisp files to run nesC under GNU Emacs
gcl-emacs-el.noarch : Source for Emacs mode for interacting with GCL
undertaker-emacs-el.noarch : Source for Emacs support for undertaker
xemacs-riece.noarch : Compiled elisp files to run Riece under XEmacs
emacs-epix.noarch : Compiled elisp files to run epix under GNU Emacs
emacs-erlang-lfe.noarch : Emacs major mode for Lisp Flavoured Erlang
emacs-gettext.noarch : Support for editing po files within GNU Emacs
emacs-magit.noarch : Emacs interface to the most common Git operations
emacs-pymacs-el.noarch : Elisp source files for pymacs under GNU Emacs
emacs-riece.noarch : Compiled elisp files to run Riece under GNU Emacs
gcl-xemacs-el.noarch : Source for XEmacs mode for interacting with GCL
tmda-emacs.noarch : Tagged Message Deliver Agent - Emacs Support Files
undertaker-xemacs-el.noarch : Source for XEmacs support for undertaker
xemacs-w3m.noarch : Compiled elisp files to run Emacs-w3m Under XEmacs
emacs-common-riece.noarch : Yet Another IRC Client for Emacs and XEmacs
emacs-ess.noarch : Files to run Emacs Speaks Statistics under GNU Emacs
emacs-cdargs-el.noarch : Elisp source files for Cdargs support for Emacs
emacs-w3m.noarch : Compiled elisp files to run Emacs-w3m under GNU Emacs
xemacs-erlang.noarch : Compiled elisp files for erlang-mode under XEmacs
emacs-dinotrace.x86_64 : Elisp source files for dinotrace under GNU Emacs
emacs-gnu-smalltalk-el.noarch : ELisp source files for emacs-gnu-smaltalk
flim-xemacs.noarch : Basic library for handling email messages for XEmacs
xemacs-erlang-el.noarch : Elisp source files for erlang-mode under XEmacs
emacs-common-ess.noarch : Emacs Speaks Statistics add-on package for Emacs
emacs-erlang.noarch : Compiled elisp files for erlang-mode under GNU Emacs
emacs-goto-chg.noarch : Emacs add-on to go to last change in current buffer
emacs-lua-el.noarch : Elisp source files for Lua major mode under GNU Emacs
protobuf-emacs.x86_64 : Emacs mode for Google Protocol Buffers descriptions
python-ropemacs.noarch : Plugin for performing python refactorings in emacs
xemacs-tuareg.noarch : Compiled elisp files to run Tuareg-mode under XEmacs
emacs-erlang-el.noarch : Elisp source files for erlang-mode under GNU Emacs
emacs-global-el.noarch : Elisp source files for GNU GLOBAL support for Emacs
emacs-rpm-spec-mode.noarch : Major GNU Emacs mode for editing RPM spec files
protobuf-emacs-el.x86_64 : Elisp source files for Google protobuf Emacs mode
xemacs-ddskk.noarch : Compiled elisp files to run Daredevil SKK under XEmacs
emacs-lookup.noarch : Search Interface with Electronic Dictionaries for Emacs
emacs-tuareg.noarch : Compiled elisp files to run Tuareg-mode under GNU Emacs
emacs-auto-complete.noarch : Intelligent auto-complete extension for GNU Emacs
emacs-ddskk.noarch : Compiled elisp files to run Daredevil SKK under GNU Emacs
emacs-irsim-mode-el.noarch : Source files for Emacs-irsim-mode under GNU Emacs
emacs-spice-mode-el.noarch : Source files for Emacs-spice-mode under GNU Emacs
emacs-vregs-mode.noarch : Elisp source files for systemc-vregs under GNU Emacs
xemacs-nox.x86_64 : Different version of Emacs built without X Windows support
emacs-systemc-mode.x86_64 : Elisp source files for systemc-mode under GNU Emacs
xemacs-xft.x86_64 : Different version of Emacs built with Xft/fontconfig support
xemacs-common.x86_64 : Byte-compiled lisp files and other common files for XEmacs
emacs-common-ebib.noarch : A BibTeX database manager that runs in Emacs and XEmacs
emacs-haskell-mode-el.noarch : Elisp source files for Haskell-mode under GNU Emacs
emacs-mmm.noarch : Emacs minor mode allowing different major modes in the same file
emacs-proofgeneral-el.noarch : Elisp source files for Proof General under GNU Emacs
emacs-proofgeneral.noarch : Compiled elisp files to run Proof General under GNU Emacs
emacs-color-theme-el.noarch : Elisp source files for Emacs Color Themes under GNU Emacs
xemacs-packages-extra-info.noarch : XEmacs packages documentation in GNU texinfo format
xemacs-packages-extra-el.noarch : Emacs lisp source files for XEmacs packages collection
emacs-auto-complete-el.noarch : Elisp source files for Auto Complete Mode under GNU Emacs
emacs-erlang-lfe-el.noarch : Elisp source files for Lisp Flavoured Erlang under GNU Emacs
emacs-common-ddskk.noarch : Daredevil SKK - Simple Kana to Kanji conversion program for Emacs
xemacs-packages-base-el.noarch : Emacs lisp source files for the base lisp packages for XEmacs
emacs-common-proofgeneral.noarch : Emacs mode for standard interaction interface for proof assistants
coq-emacs-el.noarch : Elisp source files for Coq proof management system
emacs-gtypist.x86_64 : GNU typing tutor
emacs-htmlize.noarch : Convert buffer text and decorations to HTML
emacs-undo-tree.noarch : Treats undo history as a tree of changes
emacs-auctex-doc.noarch : Documentation in various formats for AUCTeX
vile.x86_64 : VI Like Emacs
xvile.x86_64 : VI Like Emacs
zile.x86_64 : Zile Is Lossy Emacs
mg.x86_64 : Tiny Emacs-like editor
jove.x86_64 : Jonathan's Own Version of Emacs
ctags-etags.x86_64 : Exuberant Ctags for emacs tag format
psgml.noarch : GNU Emacs major mode for editing SGML documents
flim.noarch : Basic library for handling email messages for Emacs
e3.x86_64 : Text editor with key bindings similar to WordStar, Emacs, pico, nedit, or vi
[dhc-user@server1 timestudy]$
答案1
这似乎不是按长度排序的：
emacs-common-proofgeneral.noarch : Emacs mode for standard interaction interface for proof assistants
coq-emacs-el.noarch : Elisp source files for Coq proof management system
emacs-gtypist.x86_64 : GNU typing tutor
文档说，
结果按从最相关到最不相关的结果的顺序排序。
这是有道理的。这可能是算法匹配相关性的次要影响。如果相关性算法如下所示：
relevancy = letters_of_found_string / length_of_string_searched_in
那么它将首先显示较短的字符串。它可能不是最理想的，而且看起来很奇怪（不会是 DNF 中的第一件事），但上游邮件列表中的讨论或建议的改进github将不胜感激。
免责声明：我没有参与 DNF 开发，以上内容仅是常识和我的 Google-fu 的应用。