We can use Roo's script command to run a Roo batch execution as discussed here
roo> script --file filename
My question is in filename script content, how can I put a comment line/block?
You can put comment on roo script like the syntax of single line comment of Java.
// Your comment here
// another comment
p.s.
We may also use /* .... */ block though it is applied on one line only.