Small syntax/indentation and other obvious cleanups before rewriting

bash-folders-image-to-webp.sh

@@ -1,98 +1,67 @@
 #!/usr/bin/env bash
 
-# --
-# Description: Script that watches when new image (PNG or JPEG) are added and transform to WebP format.
-# --
-# Requirements: Install webp
-# Example Debian: $sudo apt install webp
-# --
-# Cron: @reboot bash-folders-image-to-webp.sh >/dev/null 2>&1 &
-# --
-
-# START
 set -e
 
-
-# FUNCTIONS
-
 usage() {
-    if [ "$*" != "" ] ; then
-        echo "Error: $*"
-    fi
+    [[ -n "${*}" ]] && printf '%s\n' "Error: ${*}" >&2
 
     cat << EOF
-Usage: $PROGNAME [OPTION]
-Watches when new image (PNG or JPEG) are added and transform to WebP format.
-Options:
---folder [path]  Folder path where will be monitored.
---help           Display this usage message and exit
+USAGE: ${0##*/} [OPTION] --folder PATH
+
+Watches when new image (PNG or JPEG) are added and transform to WebP format
+
+OPTIONS:
+    --help              Display this usage message and exit
+    --folder PATH       PATH to be monitored
 EOF
 
     exit 1
 }
 
 start() {
-    # Monitors the selected folder
-    inotifywait -m -e create,moved_to --format '%f' "$FOLDER_ORIGIN" |
-	while read -r filename; do
-	    # Gets the file extension
-	    extension="${filename##*.}"
-	    # Checks if the extension is in the extension list
-	    for ext in "${EXTENSIONS_TO_WATCH[@]}"; do
-		if [[ "$ext" = "$extension" ]]; then
-		    filename_output="${filename%.*}.webp"
-		    # Displays a flat file of information
-		    touch "$FOLDER_ORIGIN/$MESSAGE_WAITING"
-		    # Converts the image to WebP
-		    cwebp -q "$QUALITY" "$FOLDER_ORIGIN/$filename" -o "$FOLDER_ORIGIN/$filename_output"
-		    # Remove a flat file of information
-		    rm "$FOLDER_ORIGIN/$MESSAGE_WAITING"
-		fi
-	    done
-	done
+    inotifywait -m -e create,moved_to --format '%f' "$FOLDER_ORIGIN" | while read -r filename; do
+        extension="${filename##*.}"
+        for ext in "${EXTENSIONS_TO_WATCH[@]}"; do
+            if [[ "$ext" == "$extension" ]]; then
+                filename_output="${filename%.*}.webp"
+                touch "$FOLDER_ORIGIN/$MESSAGE_WAITING"
+                cwebp -q "$QUALITY" "$FOLDER_ORIGIN/$filename" -o "$FOLDER_ORIGIN/$filename_output"
+                rm "$FOLDER_ORIGIN/$MESSAGE_WAITING"
+            fi
+        done
+    done
 }
 
-
-# CONTROLE ARGUMENTS
-
-# Parse command line arguments
 while [[ $# -gt 0 ]]
 do
     key="$1"
     case $key in
-	--folder)
-	    FOLDER_ORIGIN="$2"
-	    shift # past argument
-	    shift # past value
-	    ;;
-	--quality)
-	    QUALITY="$2"
-	    shift # past argument
-	    shift # past value
-	    ;;
-	*)
-	    usage "Unknown option: $1"
-	    ;;
+    --folder)
+        FOLDER_ORIGIN="$2"
+        shift 2
+        ;;
+    --quality)
+        QUALITY="$2"
+        shift 2
+        ;;
+    *)
+        usage "Unknown option: $1"
+        ;;
     esac
 done
 
-# VARIABLES
-PROGNAME=$(basename "$0")
 QUALITY="90"
 MESSAGE_WAITING="converting_please_wait"
 EXTENSIONS_TO_WATCH=("jpg" "jpeg" "png")
 
-# CHECKS
-
-# Check if exists cwebp
-if ! which cwebp > /dev/null; then
-    echo "Error: You must install the WebP terminal tools."
+if ! command -v cwebp > /dev/null; then
+	printf '%s\n' "Error: You must install WebP tooling" >&2
     exit 1
 fi
 
 # Check if the required --folder flag is provided
-if [ -z "$FOLDER_ORIGIN" ]; then
-    echo "Error: The --folder flag is required."
+if [[ -z "$FOLDER_ORIGIN" ]]; then
+	printf '%s\n' "Error: The --folder flag is required" >&2
     exit 1
 fi