我习惯于在终端中输入 designer/assitant 即可运行 qt designer/qt assistant 的环境。我说的是 qt 4。我一直在安装 qtcreator 和 qt4-default 等软件包，但我得到了以下信息：
~$ assistant
assistant: could not exec '/usr/lib/x86_64-linux-gnu/qt4/bin/assistant': No such file or directory
~$ designer
designer: could not exec '/usr/lib/x86_64-linux-gnu/qt4/bin/designer': No such file or directory