t.py

#!/usr/bin/env python3

import argparse
import fileinput
import os
import socket
import sys

parser = argparse.ArgumentParser()
parser.add_argument('files', nargs='*')
args = parser.parse_args()

if args.files:
    files = args.files
else:
    files = []
    for line in fileinput.input():
        files.append(line.strip())

paths = []
for f in files:
    if not os.path.exists(f):
        print(f"Error: path '{f}' does not exist", file=sys.stderr)
        exit(1)
    paths.append(os.path.realpath(f))

print(f"rtransfer {socket.gethostname()} " + " ".join(paths))