No need to specify --colour as it defaults to auto

grc.bashrc

@@ -1,6 +1,6 @@
 GRC="$(which grc)"
 if [ "$TERM" != dumb ] && [ -n "$GRC" ]; then
-    alias colourify="$GRC -es --colour=auto"
+    alias colourify="$GRC -es"
     alias blkid='colourify blkid'
     alias configure='colourify ./configure'
     alias df='colourify df'

grc.zsh

@@ -34,7 +34,7 @@ if [[ "$TERM" != dumb ]] && (( $+commands[grc] )) ; then
   # Set alias for available commands.
   for cmd in $cmds ; do
     if (( $+commands[$cmd] )) ; then
-      alias $cmd="grc --colour=auto $(whence $cmd)"
+      alias $cmd="grc $(whence $cmd)"
     fi
   done