Rstudio-server Error

Rstudio server 绘图报错如下

No protocol specified
Error in RStudioGD() : 
  Shadow graphics device error: r error 4 (R code execution error)
In addition: Warning message:
In grDevices:::png("/tmp/RtmpviG1D3/25b75e70d311432085cf86d366b2551e.png",  :
  unable to open connection to X11 display ''

解决办法

install.packages("Cairo")
library(Cairo)
options(bitmapType='cairo')
plot(cars)