Python 3 script for running an application multiple times

run_handler.py

# Script for running an application multiple times
# 
#    usage run_handler.py "<app + args>" <times> [output.csv]
#
# This script runs the a process multiple times and reports the 
# average running time. Optionally, a file name can be provided,
# and the script will append the execution of each completed time
# into a file of that name. 
#
# The script further estimates its total running time after the
# the first run of the process completes, and will prompt the 
# user to continue if the total time exceeds threadhold_alert seconds

import subprocess
import sys
from pathlib import Path
import time
import signal

def sigint_handler(signal, frame):
    print('Interrupted by user. Aborting...')
    sys.exit(0)

# If the total running time of the script exceeds this threshold
# the user is prompted to continue
threshold_alert = 3600

if __name__ == '__main__':
    argc = len(sys.argv)
    if argc != 3 and argc != 4:
        print('usage %s "<app + args>" <times> [output.csv]' % sys.argv[0])
        sys.exit(-1)

    app_list = sys.argv[1].split(' ')

    times = float(sys.argv[2])

    if int(times) < 1:
        print("Error: Invalid number of iterations. Aborting...")
        sys.exit(-1)

    total_time = 0.0

    signal.signal(signal.SIGINT, sigint_handler)

    # remove output file of the same name
    if argc == 4:
        output_file = sys.argv[3]

        p = Path(output_file)
        if p.exists():
            prompt = "%s exists. Overwrite? (y/n): " % output_file
            text = input(prompt)
            while text.lower() != 'y' and text.lower() != 'n':
                text = input(prompt)

            if text == 'n':
                print("Aborting...")
                sys.exit(0)

            p.unlink()

    print("Executing %s %d times..." % (app_list[0],int(times)))
    print("Running first time...")
    i = int(times)
    while i > 0:
        start_time = time.time()
        try:
            result = subprocess.run(app_list, stdout=subprocess.PIPE)
        except FileNotFoundError:
            print("Error: %s not found" % app_list[0])
            sys.exit(-1)        
        elapsed_time = time.time()-start_time
        total_time += elapsed_time

        # estimate running time
        if i == int(times):
            est_time = elapsed_time*(times-1.0)
            if est_time > 3600:
                est_str = "Est. Running time %0.3f hours." % (est_time/3600)
            elif est_time > 60:
                est_str = "Est. Running time %0.3f minutes." % (est_time/60)
            else:
                est_str = "Est. Running time %0.3f seconds." % (est_time)
            if elapsed_time*(times-1.0) > threshold_alert:
                prompt = est_str + " Continue? (y/n): "
                text = input(prompt)
                while text.lower() != 'y' and text.lower() != 'n':
                    text = input(prompt)
                if text == 'n':
                    print("Aborting...")
                    sys.exit(0)
                print("Executing...")
            else: 
                print(est_str)

        if argc == 4:
            with open(output_file,'a') as f:
                f.write(str(elapsed_time) + '\n')

        i -= 1

    print("Done!")
    print("Average time = %f" % (total_time / times))

    if argc == 4:
        print("Execution times written to %s" % output_file)