Add missing shebang

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Remove unnecessary bash dependency

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Add parameter check and usage info

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Fix return type in comment

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>