python execute multiple command subprocess

Question

I have a command like

command = "su - user; cd $CONFIG; grep domain domains.xml"

And need to execute the commands one after other and capture the output of grep.

    def subprocess_cmd(command):
        fnlogs("comand = " + command)
        process = subprocess.Popen(command,stdout=subprocess.PIPE, shell=True)
        proc_stdout = process.communicate()[0].strip()
        fnlogs("proc_stdout = " +proc_stdout + "\n")

subprocess_cmd('su - user; cd $CONFIG; grep domain domains.xml')

Output says grep: domains.xml: No such file or directory, although the file exists its not able to find it.

you should verify the output of `pwd` to see that your subprocess is in the same directory. — silgon, Aug 18 '17 at 09:55

score 0 · Answer 1 · answered Aug 18 '17 at 09:57

It seems that you are not passing a value for CONFIG.

If you know the intended value within the script, you can do

d = dict(os.environ)
d["CONFIG"] = "/some/directory"
process = subprocess.Popen(command,stdout=subprocess.PIPE, shell=True, env=d)

You might also have to call sudo with -E to preserve the environment that you pass to the first outermost shell (see https://stackoverflow.com/a/8633575/693140).

On a more general note, you subcommand does not seem to do anything that you could not achieve within Python without relying on external commands. I would recommend to reconsider your approach altogether, and just open the file and extract the respective text from the string (eg using regular expressions).

What approach you suggest? the commands will be stored in a file and then executed? — Sameer, Aug 18 '17 at 10:49
Thank you @Stefan i managed to get is solved by writing output to file and split on result. — Sameer, Aug 19 '17 at 20:44

python execute multiple command subprocess

1 Answers1