diff --git a/chd_from_zip.sh b/chd_from_zip.sh
index 3726ae8..c673231 100755
--- a/chd_from_zip.sh
+++ b/chd_from_zip.sh
@@ -3,14 +3,26 @@
 ###uncomment below if required software not on system
 #sudo apt-get install -y mame-tools p7zip-full
 
-readonly sourcedir="$1"
-readonly destdir="$2"
+## Comprueba los parametros
+if [ "$#" -lt 2 ]; then
+  printf "Uso: chd_from_zip.sh SOURCEDIR DESTDIR [-remove]"
+  exit 0
+else
+  readonly sourcedir="$1"
+  readonly destdir="$2"
+fi
 
-# procesa el fitxer
+# Comprueba que exista el directorio de origen
+if [ ! -d "$1" ]; then
+  printf "El directorio %s no existe\n" "$1"
+  exit 0
+fi
+
+# Procesa los ficheros
 for zipfile in "${sourcedir}"/*.zip; do
   gameName="$(basename "$zipfile" .zip)"
 
-  if [ -f  "${destdir}/${gameName}.chd" ]; then
+  if [ -f "${destdir}/${gameName}.chd" ]; then
     echo -e "\e[1m\e[41m${gameName}.chd already exists\033[0m"
   else
     echo -e "\e[1m\e[41mExtracting ${gameName}...\033[0m"
@@ -23,11 +35,9 @@ for zipfile in "${sourcedir}"/*.zip; do
     #rm temporary directory
     rm -rdf "${destdir}/${gameName}-tmp"
   fi
-  
-  ### uncomment below to rm the original zip archive
-  #rm ./"$zipfile"
-  
-  if [ "$3" = "-remove" ]; then 
+
+  # Elimina el fichero
+  if [ "$3" = "-remove" ]; then
     rm ./"$zipfile"
   fi