Not sure if this is related, but i'd love to see more scripting languages (mostly Python) offer facilities which let them take over from shell script for more scripts and one-liners.

Think about what it would take to write this in Python right now:

  for wmv_file in $(find $1 -name '*.wmv'); do
    echo -n "${wmv_file} "
    ffmpeg -i $wmv_file ${wmv_file%.wmv}.mpg 2>&1 | grep kb/s: || echo "ERROR $?"
  done

With a few handy variables and functions predefined, this could be something like:

  for wmv_file in find(argv[1], glob="\*.wmv"):
    print(wmv_file, end=" ")
    result = do("ffmpeg", "-i", wmv_file, basename(wmv_file, ".wmv") + ".mpg")
    if result: print(grep(str(result), "kb/s:"))
    else: print("ERROR", result.status)

  for wmv in Path(sys.argv[1]).rglob("\*.wmv"):
        print(wmv, end=" ")
        r = subprocess.run(
            ["ffmpeg", "-i", wmv, wmv.with_suffix(".mpg")],
            stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
        )
        lines = [l for l in r.stdout.decode().splitlines() if "kb/s:" in l]
        print("\n".join(lines) if lines else f"ERROR {r.returncode}")