Use parenthesis instead of backticks for command substitution.

src/tools/cuetag.sh

@@ -72,8 +72,8 @@ vorbis()
 
 	(for field in $fields; do
 		value=""
-		for conv in `eval echo \\$$field`; do
-			value=`$CUEPRINT -n $1 -t "$conv\n" $cue_file`
+		for conv in $(eval echo \\$$field); do
+			value=$(CUEPRINT -n $1 -t "$conv\n" $cue_file)
 
 			if [ -n "$value" ]; then
 				echo "$field=$value"
@@ -105,8 +105,8 @@ id3()
 
 	for field in $fields; do
 		value=""
-		for conv in `eval echo \\$$field`; do
-			value=`$CUEPRINT -n $1 -t "$conv\n" $cue_file`
+		for conv in $(eval echo \\$$field); do
+			value=$(CUEPRINT -n $1 -t "$conv\n" $cue_file)
 
 			if [ -n "$value" ]; then
 				break
@@ -151,7 +151,7 @@ main()
 	cue_file=$1
 	shift
 
-	ntrack=`cueprint -d '%N' $cue_file`
+	ntrack=$(cueprint -d '%N' $cue_file)
 	trackno=1
 
 	if [ $# -ne $ntrack ]; then