multi-threading error in minimal script

[Skaperen]

i was making sure subprocess.call (via Popen) can run commands in separate processes from subthreads so i can, at least, consider threads as a way to avoid having 2 processes per concurrent command. it still won't let me leave the last bunch of commands running, but for now this gets this project going (faster backups to AWS S3).

#!/usr/bin/env python3
import subprocess,threading
m = 64
threads = [threading.Thread(target=subprocess.call,args=(['sleep',str(10000+x)],)) for x in range(1,m+1)]
[threads[x].start() for x in range(m)]
print(f'started {m} threads',flush=1)
[threads[x].join() for x in range(m)]
print(f'joined {m} threads',flush=1)