On Mon, 31 Oct 2016 08:13:54 +0000, Jon Ribbens wrote: > On 2016-10-31, Wildman <best_...@yahoo.com> wrote: >> Here is a bash command that I want to run from a python >> program: sudo grep "^user\:" /etc/shadow >> >> If I enter the command directly into a terminal it works >> perfectly. If I run it from a python program it returns an >> empty string. Below is the code I am using. Suggestions >> appreciated. >> >> cmdlist = ["sudo", "grep", '"^$USER\:"', "/etc/shadow"] >> p = subprocess.Popen(cmdlist, >> stdout=subprocess.PIPE, >> stderr=subprocess.PIPE) >> shadow, err = p.communicate() >> print shadow > > Slightly surprised that nobody's pointed out that in your bash > invocation, the first argument to grep is: > > ^user\: > > and in the Python code it is: > > "$USER\:" > > Your cmdlist should read: > > ["sudo", "grep", r"^user\:", "/etc/shadow"] > > or if you really want it to do the same as the bash: > > ["sudo", "grep", "^" + os.environ["USER"] + r"\:", "/etc/shadow"]
The above line works perfectly. I didn't occur to me to use the 'r' modifier. Thank you. Still one thing is odd. No matter what, if I use the environment variable $USER in the code, it won't work. Just returns an empty string. <scratches head> At this point that is a non-issue tho. Thanks again. -- <Wildman> GNU/Linux user #557453 -- https://mail.python.org/mailman/listinfo/python-list
