Running bash script from within python

I have a problem with the following code:

callBash.py:

import subprocess
print "start"
subprocess.call("sleep.sh")
print "end"

sleep.sh:

sleep 10

I want the “end” to be printed after 10s. (I know that this is a dumb example, I could simply sleep within python, but this simple sleep.sh file was just as a test)

Answers:

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Method 1

Making sleep.sh executable and adding shell=True to the parameter list (as suggested in previous answers) works ok. Depending on the search path, you may also need to add ./ or some other appropriate path. (Ie, change "sleep.sh" to "./sleep.sh".)

The shell=True parameter is not needed (under a Posix system like Linux) if the first line of the bash script is a path to a shell; for example, #!/bin/bash.

Method 2

If sleep.sh has the shebang #!/bin/sh and it has appropriate file permissions — run chmod u+rx sleep.sh to make sure and it is in $PATH then your code should work as is:

import subprocess

rc = subprocess.call("sleep.sh")

If the script is not in the PATH then specify the full path to it e.g., if it is in the current working directory:

from subprocess import call

rc = call("./sleep.sh")

If the script has no shebang then you need to specify shell=True:

rc = call("./sleep.sh", shell=True)

If the script has no executable permissions and you can’t change it e.g., by running os.chmod('sleep.sh', 0o755) then you could read the script as a text file and pass the string to subprocess module instead:

with open('sleep.sh', 'rb') as file:
    script = file.read()
rc = call(script, shell=True)

Method 3

Actually, you just have to add the shell=True argument:

subprocess.call("sleep.sh", shell=True)

But beware –

Warning Invoking the system shell with shell=True can be a security hazard if combined with untrusted input. See the warning under Frequently Used Arguments for details.

source

Method 4

If someone looking for calling a script with arguments

import subprocess

val = subprocess.check_call("./script.sh '%s'" % arg, shell=True)

Remember to convert the args to string before passing, using str(arg).

This can be used to pass as many arguments as desired:

subprocess.check_call("./script.ksh %s %s %s" % (arg1, str(arg2), arg3), shell=True)

Method 5

Make sure that sleep.sh has execution permissions, and run it with shell=True:

#!/usr/bin/python

import subprocess
print "start"
subprocess.call("./sleep.sh", shell=True)
print "end"

Method 6

If chmod is not working then you can also try:

import os
os.system('sh script.sh')
# you can also use bash instead of sh

Method 7

Adding an answer because I was directed here after asking how to run a bash script from python. You receive an error OSError: [Errno 2] file not found if your script takes in parameters. Lets say for instance your script took in a sleep time parameter: subprocess.call("sleep.sh 10") will not work, you must pass it as an array: subprocess.call(["sleep.sh", 10])

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