I am trying to send a variable from my code in Python to a shell command in Ubuntu. Can anyone help me with how to do that? Currently, I have
import os
s=5
command = os.popen('stress -c 5 -i 1 -m 1 --vm-bytes 128M -t s')
I want to send the s variable to this command instead of directly say the time of time-out.
Use the standard subprocess module:
import subprocess
s = 5
cmd = ['stress', '-c', '5', '-i', '1', '-m', '1',
'--vm-bytes', '128M', '-t', str(s)]
subprocess.call(cmd)
Using the subprocess module, allows each argument to be passed separately and distinctly. You only have to convert them to strings.
I'm assuming the 's' in your command string is what you want to assume the value of your variable 's'? All you need to do is this:
command = os.popen('stress -c 5 -i 1 -m 1 --vm-bytes 128M -t ' + str(s))
If I misread it and you are trying to replace the 5, it is basically the same
command = os.popen('stress -c ' + str(s) + ' -i 1 -m 1 --vm-bytes 128M -t s')
s comes from an untrusted source, it could be ; rm -rf / ;
rm -rf / doesn't work (I've tested it), you need rm -rf /* since rm won't let you delete root. Even then there are a handful of files it won't let you delete, but that will make the os nearly unusable.If you are using for example Google Colab and you are running the code with "!" in a line, you can put "$" behind the variable. for example:
folderName = "somedir"
!mkdir $folderName
or
!mkdir {folderName}
All according to This stackoverflow post
This is a string replacement operation which you can get all the info here.
Or you can just concatenate the strings together. (good tutorial)
