This article shows how to run a system command from Python and how to execute another program.
Use subprocess.run()
to run commands
Use the subprocess module in the standard library:
import subprocess
subprocess.run(["ls", "-l"])
It runs the command described by args. Note that args must be a List of Strings, and not one single String with the whole command. The run
function can take various optional arguments. More information can be found here.
subprocess.run(args, *, stdin=None, input=None, stdout=None, stderr=None, capture_output=False, shell=False, cwd=None, timeout=None, check=False, encoding=None, errors=None, text=None, env=None, universal_newlines=None, **other_popen_kwargs)
Note: In Python 3.4 and earlier, use subprocess.call()
instead of .run()
:
subprocess.call(["ls", "-l"])
Another option is to use os.system()
:
import os
os.system("ls -l")
This takes one single String as argument. However, subprocess.run()
is more powerful and more flexibel and even the official documentation recommends to use it over os.system()
.
Use subprocess.Popen()
to execute programs
To execute a child program in a new process, use subprocess.Popen()
:
import subprocess
subprocess.Popen(["/usr/bin/git", "commit", "-m", "Fixes a bug."])
Similar to .run()
it can take a lot of optional arguments which can be found here.
Warning: Using shell=True
is discouraged
Both run
and Popen
can take the keyword argument shell. If shell is True, the specified command will be executed through the shell. However, using this is strongly discouraged for security reasons! More information can be found here.