diff --git a/bes.ini b/bes.ini
index 646fe6f..d958233 100644
--- a/bes.ini
+++ b/bes.ini
@@ -10,4 +10,4 @@ description = "simple bash bes installer"
 keywords    = "bash, bes, install"
 
 [require]
-bes.echo    = 1.1
+bes.echo    = master
diff --git a/src/install.sh b/src/install.sh
index c2d0b6b..7dd84c2 100644
--- a/src/install.sh
+++ b/src/install.sh
@@ -14,7 +14,9 @@ function bes.install ()
     local path=${3:-/usr/local/bin}
     local done=1
     bes.echo.title "Installing $app ${Coff}in" "$path"
-
+    if [ -z "$app" ] || [ -s "$url" ]; then
+        bes.echo.error "in bes.install : \$app '$app' & \$url '$url' are required" 1
+    fi
     if [ -f "./$app" ]; then
         rm ./$app
     fi