尝试 运行 xdotool 但得到“无法打开显示：（空）”
Trying to to run xdotool but getting 'Can't open display: (null)'
很抱歉再次报告这个众所周知的错误消息。
对我来说没有任何用处。我正在 运行宁 MacOS Catalina，如果它很重要的话。
我在 Mac 上安装了 xdotool 和 brew 并尝试 运行
xdotool getmouselocation
后面的错误信息是
Error: Can't open display: (null)
Failed creating new xdo instance
我一直在寻找解决方案，找到了很多答案。 运行 export DISPLAY=:0 一切都很好。但这对我不起作用。
PS：为了更好地理解：DISPLAY 到底是什么意思？是我电脑的显示器吗？
X11 is no longer included with Mac, but X11 server and client libraries are available from the XQuartz project.
为什么 X11 在这种情况下很重要？
xdotool - 命令行 X11 自动化工具。
所以除了设置 export DISPLAY=:0
安装xquartz.
DISPLAY 到底是什么意思？
根据x manual
From the user's perspective, every X server has a display name of the form:
hostname:displaynumber.screennumber
This information is used by the application to determine how it should
connect to the server and which screen it should use by default (on
displays with multiple monitors):
hostname
The hostname specifies the name of the machine to which the display is physically connected. If the hostname is not given, the
most efficient way of communicating to a server on the same machine
will be used.
displaynumber
The phrase "display" is usually used to refer to collection of monitors that share a common keyboard and pointer (mouse, tablet,
etc.). Most workstations tend to only have one keyboard, and
therefore, only one display. Larger, multi-user systems, however,
frequently have several displays so that more than one person can be
doing graphics work at once. To avoid confusion, each display on a
machine is assigned a display number (beginning at 0) when the X
server for that display is started. The display number must always be
given in a display name.
screennumber
Some displays share a single keyboard and pointer among two or more monitors. Since each monitor has its own set of windows, each
screen is assigned a screen number (beginning at 0) when the X server
for that display is started. If the screen number is not given, screen
0 will be used.
找到了更简单的描述here
显示包括（简化）：
- 一个键盘
- 一只老鼠
- 一个屏幕
即当您通过 ssh 连接时，您使用的是这 3 个的不同集合。
很抱歉再次报告这个众所周知的错误消息。
对我来说没有任何用处。我正在 运行宁 MacOS Catalina，如果它很重要的话。
我在 Mac 上安装了 xdotool 和 brew 并尝试 运行
xdotool getmouselocation
后面的错误信息是
Error: Can't open display: (null)
Failed creating new xdo instance
我一直在寻找解决方案，找到了很多答案。 运行 export DISPLAY=:0 一切都很好。但这对我不起作用。
PS：为了更好地理解：DISPLAY 到底是什么意思？是我电脑的显示器吗？
X11 is no longer included with Mac, but X11 server and client libraries are available from the XQuartz project.
为什么 X11 在这种情况下很重要？
xdotool - 命令行 X11 自动化工具。
所以除了设置 export DISPLAY=:0
安装xquartz.
DISPLAY 到底是什么意思？
根据x manual
From the user's perspective, every X server has a display name of the form:
hostname:displaynumber.screennumberThis information is used by the application to determine how it should connect to the server and which screen it should use by default (on displays with multiple monitors):
hostname The hostname specifies the name of the machine to which the display is physically connected. If the hostname is not given, the most efficient way of communicating to a server on the same machine will be used.
displaynumber The phrase "display" is usually used to refer to collection of monitors that share a common keyboard and pointer (mouse, tablet, etc.). Most workstations tend to only have one keyboard, and therefore, only one display. Larger, multi-user systems, however, frequently have several displays so that more than one person can be doing graphics work at once. To avoid confusion, each display on a machine is assigned a display number (beginning at 0) when the X server for that display is started. The display number must always be given in a display name.
screennumber Some displays share a single keyboard and pointer among two or more monitors. Since each monitor has its own set of windows, each screen is assigned a screen number (beginning at 0) when the X server for that display is started. If the screen number is not given, screen 0 will be used.
找到了更简单的描述here
显示包括（简化）：
- 一个键盘
- 一只老鼠
- 一个屏幕
即当您通过 ssh 连接时，您使用的是这 3 个的不同集合。