diff --git a/aliases.sh b/aliases.sh
index b3621f7..30b9c52 100755
--- a/aliases.sh
+++ b/aliases.sh
@@ -72,7 +72,7 @@ alias ssh1="ssh -o ControlMaster=no"
 
 
 # Some colorizing options for grc
-if [[ "$TERM" != dumb ]] && (( $+commands[grc] )) ; then
+if [[ "$TERM" != dumb ]] && [[ -f $(which grc) ]] ; then
   # Prevent grc aliases from overriding zsh completions.
   setopt COMPLETE_ALIASES
 
@@ -89,7 +89,6 @@ if [[ "$TERM" != dumb ]] && (( $+commands[grc] )) ; then
     ifconfig \
     last \
     ldap \
-    ls \
     make \
     mount \
     mtr \
@@ -104,7 +103,7 @@ if [[ "$TERM" != dumb ]] && (( $+commands[grc] )) ; then
 
   # Set alias for available commands.
   for cmd in $cmds ; do
-    if (( $+commands[$cmd] )) ; then
+    if [[ -f $(which $cmd) ]] ; then
       alias $cmd="grc --colour=auto $cmd"
     fi
   done