pywait.py - execute arguments whenever a file changes

pywait.py

"""
pywait.py - execute arguments whenever a file changes

Terry N. Brown, terrynbrown@gmail.com, Mon Dec 12 10:47:49 2016
"""

import os
import sys
import time

def get_state():
    """return set of os.stat() for all files"""
    state = set()
    for path, dirs, files in os.walk('.'):
        for file_ in files:
            state.add((file_, os.stat(os.path.join(path, file_))))
    return state

def main():
    
    new_state = None
    cmd = ' '.join(sys.argv[1:])
    
    while True:
        if new_state is not None:
            print('\n'.join(i[0] for i in new_state.difference(state)))
        if cmd:
            os.system(cmd)
        print("RUN: %s" % time.asctime())
        new_state = state = get_state()
        while new_state == state:
            time.sleep(5)
            new_state = get_state()
        if not cmd:
            exit()

if __name__ == '__main__':
    main()