Package check result: ERROR

Check: examples, Result: ERROR
  Running examples in ‘rde-Ex.R’ failed
  The error most likely occurred in:
  
  > base::assign(".ptime", proc.time(), pos = "CheckExEnv")
  > ### Name: copy_rde_var
  > ### Title: Encode, compress and copy data into the clipboard
  > ### Aliases: copy_rde_var
  > 
  > ### ** Examples
  > 
  > ## No test: 
  > copy_rde_var(iris)
  <simpleWarning in system2(util_test[1], util_test[-1], stdout = TRUE, stderr = TRUE): running command ''xclip' -o -selection clipboard 2>&1' had status 1>
  Error: Clipboard on X11 requires that the DISPLAY envvar be configured.
  Execution halted