Question

I’m very new to python, I have a bash code which stores the result of the file into a variable like this:

variable=(`cat text`)

The variable is now has the contents of test. I tried similar in python using Popen call like this:

 subprocess.Popen("variable=(`cat text`)")

But I get error like this:

Traceback (most recent call last):
  File "./push-jenkins", line 5, in <module>
    subprocess.Popen("variable=(`cat text`)")
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

Not sure where I’m making the mistake.

Thanks in advance.

Answer 1

You cannot access bash variables from Python. Do instead:

variable = subprocess.check_output(['cat', 'text'])

I’m assuming that this command is just an example, as you can read a file from Python easy enough.

Note that the call to check_output receives the command as a split list of arguments, not as a single string. If you have a single string and don’t want do split manually you can do:

variable = subprocess.check_output(['sh', '-c', command])

Or even better:

variable = subprocess.check_output(command, shell=True)

And let the shell do the hard work.