（重新）用applescript启动python脚本

Question

I have a Python script that runs in an infinite loop (it's a server).

I want to write an AppleScript that will start this script if it isn't started yet, and otherwise force-quit and restart it. This will make it easy for me to make changes to the server code while programming.

Currently I only know how to start it: do shell script "python server.py"

Answer 1

On the shell, if you do ps aux | grep python\\ server.py | head -n1 ps aux | grep python\\ server.py | head -n1 ps aux | grep python\\ server.py | head -n1 , you'll get the ID of the process running server.py . You can then use kill -9 to kill that process and restart it:

kill -9 `ps aux | grep python\ server.py | head -n1 | python -c 'import sys; print(sys.stdin.read().split()[1])'`

That'll kill it. Al you have to do now is to restart it:

python server.py

You can combine the two with && :

kill -9 `ps aux | grep python\ server.py | head -n1 | python -c 'import sys; print(sys.stdin.read().split()[1])'` && python server.py

Of course, you already know how to put that in a do shell script !

Answer 2

Note that AppleScript's do shell script starts the shell ( /bin/sh ) in the root directory ( / ) by default, so you should specify an explicit path to server.py

In the following examples I'll assume directory path ~/srv .

Here's the shell command:

pid=$(pgrep -fx 'python .*/server\.py'); [ "$pid" ] && kill -9 $pid; python ~/srv/server.py

As an AppleScript statement, wrapped in do shell script - note the \\ -escaped inner " and \\ chars.:

do shell script "pid=$(pgrep -fx 'python .*/server\\.py'); [ \"$pid\" ] && kill -9 $pid; python ~/srv/server.py"

• pgrep -fx '^python .*/server\\.py$' uses pgrep to find your running command by regex against the full command line ( -f ), requiring a full match ( -x ), and returns the PID (process ID), if any.

  • Note that I've used a more abstract regex to underscore the fact that pgrep (always) treats its search term as a regular expression .
    To specify the full launch command line as the regex, use python ~/srv/server\\.py - note the \\ -escaping of . for full robustness.

• [ "$pid" ] && kill -9 $pid kills the process, if a PID was found ( [ "$pid" ] is short for [ -n "$pid" ] and evaluates to true only if $pid is nonempty); -9 sends signal SIGKILL , which forcefully terminates the process.

• python ~/srv/server.py then (re)starts your server.