为什么对于图形应用程序，pkexec优于gksudo？

请提供驳斥此内容的Ubuntu文档：https : //help.ubuntu.com/community/RootSudo为什么在我完全更新的13.04系统上，pkexec无法正常运行？

$ pkexec gedit somefile.txt
No protocol specified

** (gedit:13135): WARNING **: Could not open X display
Cannot open display: 
Run '/usr/bin/gedit --help' to see a full list of available command line options

为什么不起作用？

默认情况下pkexec，不允许您运行图形（X11）应用程序。从手册页：

 The environment that PROGRAM will run it, will be set to a minimal
 known and safe environment in order to avoid injecting code through
 LD_LIBRARY_PATH or similar mechanisms. In addition the PKEXEC_UID
 environment variable is set to the user id of the process invoking
 pkexec.
     As a result, pkexec will not allow you to run X11 applications
     as another user since the $DISPLAY and $XAUTHORITY environment
     variables are not set.
 These two variables will be retained if the
 org.freedesktop.policykit.exec.allow_gui annotation on an action is set
 to a nonempty value; this is discouraged, though, and should only be
 used for legacy programs.

正如手册页中所述，尽管我真的不知道这在某种程度上是危险的还是值得推荐的，但是您可以使其正常运行。

例如，要启用gedit，您可以创建/usr/share/polkit-1/actions/com.ubuntu.gedit.policy以下内容：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policyconfig PUBLIC
 "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/PolicyKit/1.0/policyconfig.dtd">
<policyconfig>
  <vendor>gedit</vendor>
  <vendor_url>gedit</vendor_url>
  <icon_name>accessories-text-editor</icon_name>
  <action id="org.freedesktop.policykit.pkexec.gedit">
   <description>Run "gedit"</description>
   <message>Authentication is required to run Text Editor</message>
   <defaults>
     <allow_any>auth_admin</allow_any>
     <allow_inactive>auth_admin</allow_inactive>
     <allow_active>auth_admin</allow_active>
   </defaults>
     <annotate key="org.freedesktop.policykit.exec.path">/usr/bin/gedit</annotate>
     <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>
   </action>  
</policyconfig>

然后pkexec gedit应按预期工作：

如您所料，这只会gedit起作用。从理论上讲，如果您添加allow_gui到“ org.freedesktop.policykit.exec”（默认操作），则该方法应适用于所有应用程序，但是在我的测试中，我得到的结果与您的相同。

为什么首选pkexec？

在这里，您可以找到有关的优势的讨论pkexec。