$ pip install pywatcher

usage: pywatcher [-h] -t TARGET_DIR_PATH -c TARGET_COMMAND_STR
                 [-s RELOAD_THRESHOLD_SECONDS] [--disable-capture-stdout]
                 [-p [TARGET_PATTERN [TARGET_PATTERN ...]]]
                 [--signal {TERM,KILL}]

-----------------------------------------------------------------------
PyWatcher:

monitor file and reload process. like gulp watch

e.g:

pywatcher -t .  -c 'ping localhost'
-> if some file on current dir changed, restart process 'ping localhost'.

-----------------------------------------------------------------------

optional arguments:
  -h, --help            show this help message and exit
  -t TARGET_DIR_PATH, --target-dir TARGET_DIR_PATH
                        target directory for watching.
  -c TARGET_COMMAND_STR, --command TARGET_COMMAND_STR
                        target command. this command execute and restart when file changed.
  -s RELOAD_THRESHOLD_SECONDS, --reload-interval-seconds RELOAD_THRESHOLD_SECONDS
                        reload threshold seconds.
  --reload-wait-seconds RELOAD_WAIT_SECONDS
                        reload wait seconds.
  --disable-capture-stdout
                        is_disable_capture_stdout
  -p [TARGET_PATTERN [TARGET_PATTERN ...]], --pattern [TARGET_PATTERN [TARGET_PATTERN ...]]
                        target pattern for monitoring. default, all file match.
  --signal {TERM,KILL}  reload_signal
  --is-use-shell        use shell=True ?

(pywatcher) denzownoMacBook-Pro:pywatcher denzow$ pywatcher -t. -c 'ping localhost'
2018-03-11 23:35:37,114 - INFO - [start process]: ping localhost
2018-03-11 23:35:37,124 - DEBUG - [subprocess_output]: PING localhost (127.0.0.1): 56 data bytes
2018-03-11 23:35:37,124 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.043 ms
2018-03-11 23:35:38,129 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.132 ms
2018-03-11 23:35:39,133 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.161 ms
2018-03-11 23:35:40,138 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.152 ms
2018-03-11 23:35:41,142 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.062 ms
2018-03-11 23:35:42,147 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=5 ttl=64 time=0.095 ms
2018-03-11 23:35:43,141 - INFO - [reload process]: ping localhost  <-- file changed. so reload 
2018-03-11 23:35:43,141 - DEBUG - [subprocess_output]: b''
2018-03-11 23:35:43,141 - INFO - [start process]: ping localhost
2018-03-11 23:35:43,149 - DEBUG - [subprocess_output]: PING localhost (127.0.0.1): 56 data bytes
2018-03-11 23:35:43,149 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.044 ms
2018-03-11 23:35:44,152 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.063 ms
2018-03-11 23:35:45,152 - DEBUG - [subprocess_output]: 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.048 ms

(pywatcher) denzownoMacBook-Pro:pywatcher denzow$ pywatcher -t. -c 'ping localhost' --disable-capture-stdout
2018-03-11 23:36:12,559 - INFO - [start process]: ping localhost
2018-03-11 23:36:19,136 - INFO - [reload process]: ping localhost  <-- file changed. so reload
2018-03-11 23:36:19,136 - INFO - [start process]: ping localhost
:

(pywatcher) denzownoMacBook-Pro:pywatcher denzow$ pywatcher -t ./ -c 'ping localhost' -p '*.py'

(pywatcher) denzownoMacBook-Pro:pywatcher denzow$ python pywatcher/command.py -t . -c 'echo reload'  -s 1 --signal KILL
2018-05-03 11:57:37,940 - INFO - [start process]: echo reload
2018-05-03 11:57:37,945 - INFO - [start process]: PID is 4885
2018-05-03 11:57:37,952 - DEBUG - [subprocess_output]: reload
2018-05-03 11:57:46,657 - INFO - [reload process]: echo reload
2018-05-03 11:57:46,657 - DEBUG - KILL signal send to process
2018-05-03 11:57:46,657 - INFO - [start process]: echo reload
2018-05-03 11:57:46,660 - INFO - [start process]: PID is 4887
2018-05-03 11:57:46,662 - DEBUG - [subprocess_output]: reload