improved readabality

tools/append_or_replace

@@ -1,22 +1,19 @@
 #!/bin/bash
 
-usage() {
-	echo "Usage: $(basename "$0") <REGEX> <STRING> <FILE>"
+function usage {
+	builtin echo "Usage: $(basename "$0") <REGEX> <STRING> <FILE>"
 }
 
-if [[ $# -ne 3 ]]; then
-	usage
-	exit 2
-fi
+[[ $# -ne 3 ]] && usage && exit 2
 
 REGEX=$1
 STRING=$2
 FILE=$3
 
 if ! grep -Eq "$REGEX" "$FILE"; then
-	printf "$STRING\n" >>$FILE
-	echo appended
+	printf "%s\n" "$STRING" >>"$FILE"
+	echo 'appended'
 else
-	sed -Ei "s|$REGEX|$STRING|g" $FILE
-	echo replaced
+	sed -Ei "s|$REGEX|$STRING|g" "$FILE"
+	echo 'replaced'
 fi