use bstr::ByteSlice;

use std::os::unix::ffi::OsStrExt;

    Command::new(command)
        .args(args)
        .arg(filename)
        .status()?
        .exit_ok()?;

    let bfilename = filename.as_os_str().as_bytes();
    let args = args
        .iter()
        .map(|arg| OsStr::from_bytes(&arg.as_bytes().replace("%f", bfilename)).to_owned());
    Command::new(command).args(args).status()?.exit_ok()?;

args = ["/path/to/upload.py"]

args = ["/path/to/upload.py", "%f"]  # %f is replaced with a filename

bstr = "^1.0.1"