How To Capture Output Of Subprocess.call

I have made a script that tells me the temperature of my Raspberry Pi 3, but there is a problem with the script. The result output is the bot saying 'Your RPI3 temp is currently 0

Solution 1:

return_code will have the return code of the process. When a process exists successfully (without error), it returns a code of 0. If it errors, it returns a code of 1 (or something non-zero). If you want the output of the program (that it prints to stdout), this is one way to get it:

p = subprocess.run("vcgencmd measure_temp", shell=True,stdout=subprocess.PIPE)
result = p.stdout.decode()
await bot.say("Your RPI3 temp is currently: {}".format(result))

Solution 2:

You should use subprocess.check_output to get the response from your command.

From the docs:

subprocess.check_output(args, *, stdin=None, stderr=None, shell=False, universal_newlines=False)

Run command with arguments and return its output as a byte string.

Using call gives the returncode:

subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False)

Run the command described by args. Wait for command to complete, then return the returncode attribute.