diff --git a/completion/available/knife.completion.bash b/completion/available/knife.completion.bash
index 191e428c..9b370209 100644
--- a/completion/available/knife.completion.bash
+++ b/completion/available/knife.completion.bash
@@ -19,7 +19,7 @@ _KNIFE_AUTOCOMPLETE_MAX_CACHE_AGE=86400
 ### init
 _KAC_CACHE_TMP_DIR="$_KNIFE_AUTOCOMPLETE_CACHE_DIR/tmp"
 # make sure the cache dir exists
-mkdir -p $_KAC_CACHE_TMP_DIR
+mkdir -p "$_KAC_CACHE_TMP_DIR"
 
 ##############################
 ### Cache helper functions ###
@@ -33,7 +33,7 @@ stat -c %Y /dev/null > /dev/null 2>&1 && _KAC_STAT_COMMAND="stat -c %Y" || _KAC_
 # returns 1 otherwise
 _KAC_is_file_newer_than() {
 	[ -f "$1" ] || return 1
-	[ $(($(date +%s) - $($_KAC_STAT_COMMAND "$1"))) -gt $2 ] && return 1 || return 0
+	[ $(($(date +%s) - $($_KAC_STAT_COMMAND "$1"))) -gt "$2" ] && return 1 || return 0
 }
 
 # helper function for _KAC_get_and_regen_cache, see doc below
@@ -42,10 +42,10 @@ _KAC_regen_cache() {
 	local CACHE_PATH="$_KNIFE_AUTOCOMPLETE_CACHE_DIR/$CACHE_NAME"
 	local TMP_FILE=$(mktemp "$_KAC_CACHE_TMP_DIR/$CACHE_NAME.XXXX")
 	shift 1
-	"$@" > $TMP_FILE 2> /dev/null
+	"$@" > "$TMP_FILE" 2> /dev/null
 	# discard the temp file if it's empty AND the previous command didn't exit successfully, but still mark the cache as updated
-	[[ $? != 0 ]] && [[ $(cat $TMP_FILE | wc -l) == 0 ]] && rm -f $TMP_FILE && touch $CACHE_PATH && return 1 \
-		|| mv -f $TMP_FILE $CACHE_PATH
+	[[ $? != 0 ]] && [[ $(wc -l "$TMP_FILE") == 0 ]] && rm -f "$TMP_FILE" && touch "$CACHE_PATH" && return 1 \
+		|| mv -f "$TMP_FILE" "$CACHE_PATH"
 }
 
 # cached files can't have spaces in their names
@@ -65,10 +65,14 @@ _KAC_get_command_from_cache_name() {
 _KAC_get_and_regen_cache() {
 	# the cache name can't have space in it
 	local CACHE_NAME=$(_KAC_get_cache_name_from_command "$@")
-	local REGEN_CMD="_KAC_regen_cache $CACHE_NAME $@"
+	local REGEN_CMD="_KAC_regen_cache $CACHE_NAME $*"
 	_KAC_CACHE_PATH="$_KNIFE_AUTOCOMPLETE_CACHE_DIR/$CACHE_NAME"
 	# no need to wait for the regen if the file already exists
-	[ -f $_KAC_CACHE_PATH ] && ($REGEN_CMD &) || $REGEN_CMD
+	if [[ -f "$_KAC_CACHE_PATH" ]]; then
+		($REGEN_CMD &)
+	else
+		$REGEN_CMD
+	fi
 }
 
 # performs two things: first, deletes all obsolete temp files
@@ -76,17 +80,18 @@ _KAC_get_and_regen_cache() {
 _KAC_clean_cache() {
 	local FILE CMD
 	# delete all obsolete temp files, could be lingering there for any kind of crash in the caching process
-	for FILE in $(ls $_KAC_CACHE_TMP_DIR); do
-		_KAC_is_file_newer_than $FILE $_KNIFE_AUTOCOMPLETE_MAX_CACHE_AGE || rm -f $FILE
+	for FILE in $(\ls "$_KAC_CACHE_TMP_DIR"); do
+		_KAC_is_file_newer_than "$FILE" "$_KNIFE_AUTOCOMPLETE_MAX_CACHE_AGE" || rm -f "$FILE"
 	done
 	# refresh really stale caches
-	for FILE in $(find $_KNIFE_AUTOCOMPLETE_CACHE_DIR -maxdepth 1 -type f -not -name '.*'); do
-		_KAC_is_file_newer_than $FILE $_KNIFE_AUTOCOMPLETE_MAX_CACHE_AGE && continue
-		# first let's get the original command
-		CMD=$(_KAC_get_command_from_cache_name $(basename "$FILE"))
-		# then regen the cache
-		_KAC_get_and_regen_cache "$CMD" > /dev/null
-	done
+	find "$_KNIFE_AUTOCOMPLETE_CACHE_DIR" -maxdepth 1 -type f -not -name '.*' \
+		| while read -r FILE; do
+			_KAC_is_file_newer_than "$FILE" "$_KNIFE_AUTOCOMPLETE_MAX_CACHE_AGE" && continue
+			# first let's get the original command
+			CMD=$(_KAC_get_command_from_cache_name "$(basename "$FILE")")
+			# then regen the cache
+			_KAC_get_and_regen_cache "$CMD" > /dev/null
+		done
 }
 
 # perform a cache cleaning when loading this file
@@ -109,32 +114,32 @@ _KAC_get_current_base_command() {
 	local PREVIOUS="knife"
 	local I=1
 	local CURRENT
-	while [ $I -le $COMP_CWORD ]; do
+	while [ $I -le "$COMP_CWORD" ]; do
 		# command words are all lower-case
-		echo ${COMP_WORDS[$I]} | grep -E "^[a-z]+$" > /dev/null || break
+		echo "${COMP_WORDS[$I]}" | grep -E "^[a-z]+$" > /dev/null || break
 		CURRENT="$PREVIOUS ${COMP_WORDS[$I]}"
-		cat $_KAC_CACHE_PATH | grep -E "^$CURRENT" > /dev/null || break
+		grep -E "^$CURRENT" "$_KAC_CACHE_PATH" > /dev/null || break
 		PREVIOUS=$CURRENT
-		I=$(($I + 1))
+		I=$((I + 1))
 	done
 	_KAC_CURRENT_COMMAND=$PREVIOUS
-	[ $I -le $COMP_CWORD ] && _KAC_CURRENT_COMMAND_NB_WORDS=$I
+	[ $I -le "$COMP_CWORD" ] && _KAC_CURRENT_COMMAND_NB_WORDS=$I
 }
 
 # searches the position of the currently completed argument in the current base command
 # (i.e. handles "plural" arguments such as knife cookbook upload cookbook1 cookbook2 and so on...)
 # assumes the current base command is complete
 _KAC_get_current_arg_position() {
-	local CURRENT_ARG_POS=$(($_KAC_CURRENT_COMMAND_NB_WORDS + 1))
-	local COMPLETE_COMMAND=$(cat $_KAC_CACHE_PATH | grep -E "^$_KAC_CURRENT_COMMAND")
+	local CURRENT_ARG_POS=$((_KAC_CURRENT_COMMAND_NB_WORDS + 1))
+	local COMPLETE_COMMAND=$(grep -E "^$_KAC_CURRENT_COMMAND" "$_KAC_CACHE_PATH")
 	local CURRENT_ARG
-	while [ $CURRENT_ARG_POS -le $COMP_CWORD ]; do
-		CURRENT_ARG=$(echo $COMPLETE_COMMAND | cut -d ' ' -f $CURRENT_ARG_POS)
+	while [ "$CURRENT_ARG_POS" -le "$COMP_CWORD" ]; do
+		CURRENT_ARG=$(echo "$COMPLETE_COMMAND" | cut -d ' ' -f "$CURRENT_ARG_POS")
 		# we break if the current arg is a "plural" arg
-		echo $CURRENT_ARG | grep -E "^\\[[^]]+(\\.\\.\\.\\]|$)" > /dev/null && break
-		CURRENT_ARG_POS=$(($CURRENT_ARG_POS + 1))
+		echo "$CURRENT_ARG" | grep -E "^\\[[^]]+(\\.\\.\\.\\]|$)" > /dev/null && break
+		CURRENT_ARG_POS=$((CURRENT_ARG_POS + 1))
 	done
-	echo $CURRENT_ARG_POS
+	echo "$CURRENT_ARG_POS"
 }
 
 # the actual auto-complete function
@@ -143,8 +148,8 @@ _knife() {
 	local RAW_LIST ITEM REGEN_CMD ARG_POSITION
 	COMREPLY=()
 	# get correct command & arg pos
-	_KAC_get_current_base_command && ARG_POSITION=$(_KAC_get_current_arg_position) || ARG_POSITION=$(($COMP_CWORD + 1))
-	RAW_LIST=$(cat $_KAC_CACHE_PATH | grep -E "^$_KAC_CURRENT_COMMAND" | cut -d ' ' -f $ARG_POSITION | uniq)
+	_KAC_get_current_base_command && ARG_POSITION=$(_KAC_get_current_arg_position) || ARG_POSITION=$((COMP_CWORD + 1))
+	RAW_LIST=$(grep -E "^$_KAC_CURRENT_COMMAND" "$_KAC_CACHE_PATH" | cut -d ' ' -f $ARG_POSITION | uniq)
 
 	# we need to process that raw list a bit, most notably for placeholders
 	# NOTE: I chose to explicitely fetch & cache _certain_ informations for the server (cookbooks & node names, etc)
@@ -154,13 +159,13 @@ _knife() {
 	LIST=""
 	for ITEM in $RAW_LIST; do
 		# always relevant if only lower-case chars : continuation of the base command
-		echo $ITEM | grep -E "^[a-z]+$" > /dev/null && LIST="$LIST $ITEM" && continue
-		case $ITEM in
+		echo "$ITEM" | grep -E "^[a-z]+$" > /dev/null && LIST="$LIST $ITEM" && continue
+		case "$ITEM" in
 			*COOKBOOK*)
 				# special case for cookbooks : from site or local
 				[[ ${COMP_WORDS[2]} == 'site' ]] && REGEN_CMD="knife cookbook site list" || REGEN_CMD="knife cookbook list"
-				_KAC_get_and_regen_cache $REGEN_CMD
-				LIST="$LIST $(cat $_KAC_CACHE_PATH | cut -d ' ' -f 1)"
+				_KAC_get_and_regen_cache "$REGEN_CMD"
+				LIST="$LIST $(cut -d ' ' -f 1 < "$_KAC_CACHE_PATH")"
 				continue
 				;;
 			*ITEM*)
@@ -182,8 +187,8 @@ _knife() {
 			# not a generic argument we support...
 			*) continue ;;
 		esac
-		_KAC_get_and_regen_cache $REGEN_CMD
-		LIST="$LIST $(cat $_KAC_CACHE_PATH)"
+		_KAC_get_and_regen_cache "$REGEN_CMD"
+		LIST="$LIST $(cat "$_KAC_CACHE_PATH")"
 	done
 	COMPREPLY=($(compgen -W "${LIST}" -- ${COMP_WORDS[COMP_CWORD]}))
 }