diff --git a/modules/utility/init.zsh b/modules/utility/init.zsh
index a38150d..cacd8be 100644
--- a/modules/utility/init.zsh
+++ b/modules/utility/init.zsh
@@ -76,7 +76,9 @@ if zstyle -T ':prezto:module:utility' safe-ops; then
 fi
 
 # ls
-if [[ ${(@M)${(f)"$(ls --version 2>&1)"}:#*(GNU|lsd|uutils) *} ]]; then
+_ls_version="$(ls --version 2>&1)"
+
+if [[ ${(@M)${(f)_ls_version}:#*(GNU|lsd|uutils) *} ]]; then
   # GNU Core Utilities
 
   if zstyle -T ':prezto:module:utility:ls' dirs-first; then
@@ -123,10 +125,12 @@ alias lt='ll -tr'        # Lists sorted by date, most recent last.
 alias lc='lt -c'         # Lists sorted by date, most recent last, shows change time.
 alias lu='lt -u'         # Lists sorted by date, most recent last, shows access time.
 
-if [[ ${(@M)${(f)"$(ls --version 2>&1)"}:#*GNU *} ]]; then
+if [[ ${(@M)${(f)_ls_version}:#*GNU *} ]]; then
   alias lx='ll -XB'      # Lists sorted by extension (GNU only).
 fi
 
+unset _ls_version
+
 # Grep
 if zstyle -t ':prezto:module:utility:grep' color; then
   export GREP_COLOR=${GREP_COLOR:-'37;45'}            # BSD.