Bencedit can edit files interactively from the command line or process several files in batch mode. It is still very WIP right now and only has a couple of simple commands.
bencedit [FLAGS] [OPTIONS] <files>...
FLAGS:
-b, --batch Process several files through transforms
-h, --help Prints help information
-S, --skip-invalid In batch mode, skip invalid files
-N, --skip-not-found In batch mode, skip non-existant files
-V, --version Prints version information
OPTIONS:
-t, --transform <transform>... An action to apply to files in batch mode
ARGS:
<files>...
See the command list and the transform list.