Be more specific with export/import command options

usr/local/share/bastille/export.sh

@@ -49,6 +49,8 @@ usage() {
     -v | --verbose  -- Be more verbose during the ZFS send operation.
          --xz       -- Export a ZFS jail using XZ(.xz) compressed image.
 
+Tip: If no option specified, container should be exported to standard output.
+
 EOF
     exit 1
 }

usr/local/share/bastille/import.sh

@@ -42,6 +42,8 @@ usage() {
     -f | --force    -- Force an archive import regardless if the checksum file does not match or missing.
     -v | --verbose  -- Be more verbose during the ZFS receive operation.
 
+Tip: If no option specified, container should be imported from standard input.
+
 EOF
     exit 1
 }