[gazebo_gui-2] process has died [pid 7444, exit code 134, cmd /opt/ros/melodic/lib/gazebo_ros/gzclie

[gazebo_gui-2] process has died [pid 7444, exit code 134, cmd /opt/ros/melodic/lib/gazebo_ros/gzclient __name:=gazebo_gui __log:=/home/chen/.ros/log/ea94e344-1b03-11ed-9006-000c29879dc2/gazebo_gui-2.log].
log file: /home/chen/.ros/log/ea94e344-1b03-11ed-9006-000c29879dc2/gazebo_gui-2*.log

错误原因：主要是gazebo在之前的操作中打开过，而没有完全的关闭，使用ctrl+c仅关闭了了gazebo的gui界面，并没有完全关闭gazebo。

解决方法：

输入指令：

killall gzserver && killall gzclient