Don't call in to xclip when $DISPLAY isn't available.

dotfiles/lib/shellenv/functions.sh

@@ -121,7 +121,7 @@ function oscopy() {
     then
         reattach-to-user-namespace pbcopy
     else
-	xclip -selection c
+	test -n "$DISPLAY" && xclip -selection c
     fi
 }
 

dotfiles/lib/zsh/system-wide-clipboard.zsh

@@ -1,32 +1,32 @@
 pb-kill-line () {
   zle kill-line
-  echo -n $CUTBUFFER | clipboard
+  echo -n $CUTBUFFER | oscopy
 }
 
 pb-kill-whole-line () {
   zle kill-whole-line
-  echo -n $CUTBUFFER | clipboard
+  echo -n $CUTBUFFER | oscopy
 }
 
 pb-backward-kill-word () {
   zle backward-kill-word
-  echo -n $CUTBUFFER | clipboard
+  echo -n $CUTBUFFER | oscopy
 }
 
 pb-kill-word () {
   zle kill-word
-  echo -n $CUTBUFFER | clipboard
+  echo -n $CUTBUFFER | oscopy
 }
 
 pb-kill-buffer () {
   zle kill-buffer
-  echo -n $CUTBUFFER | clipboard
+  echo -n $CUTBUFFER | oscopy
 }
 
 pb-copy-region-as-kill-deactivate-mark () {
   zle copy-region-as-kill
   zle set-mark-command -n -1
-  echo -n $CUTBUFFER | clipboard
+  echo -n $CUTBUFFER | oscopy
 }
 
 pb-yank () {