Suppose I have 3 sub directories. All of them contain a file named `old_file_name`. Now with a single command I want to rename all of them to `new_file_name`. 

I tried

```
sudo find . -name "old_file_name" -exec rename old_file_name new_file_name {} \;

```

But it is showing following error:

> 
> Bareword "new\_file\_name" not allowed while "strict subs" in use at (user-supplied code).
> 
> 
>