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Python: I want to execute shell commands using python script

I want to execute shell command "objdump" using python for my research work
I have used subprocess.call("command") to execute linux command but its not working.
Sample code which i have tried is
import subprocess
subprocess.call("date")
after the execution
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\subprocess.py", line 168, in call
return Popen(*popenargs, **kwargs).wait()
File "C:\Python27\lib\subprocess.py", line 390, in __init__
errread, errwrite)
File "C:\Python27\lib\subprocess.py", line 640, in _execute_child
startupinfo)
WindowsError: [Error 2] The system cannot find the file specified

You must do this:
subprocess.call('date', shell=True)
Actually, Shell does allow you to access to global variable and programs that are in $PATH and your shell.

Have you tried ?
import subprocess
subprocess.call("date", shell = True)

Getting error with subprocess while running aws s3 cp: [Errno 2] No such file or directory: 'aws'

I am able to execute this command successfully from command line and it copies the desired csv to the s3 bucket aws s3 cp /Users/kaswani/tips.csv s3://dplearn/
But, when I try to run the same from within python using subprocess it throws error:
subprocess.check_output(['aws','s3','cp','/Users/kaswani/tips.csv','s3://dplearn/'])
Error:
Traceback (most recent call last):
File "<input>", line 1, in <module>
File "/Users/kaswani/anaconda/envs/aws/lib/python3.5/subprocess.py", line 626, in check_output
**kwargs).stdout
File "/Users/kaswani/anaconda/envs/aws/lib/python3.5/subprocess.py", line 693, in run
with Popen(*popenargs, **kwargs) as process:
File "/Users/kaswani/anaconda/envs/aws/lib/python3.5/subprocess.py", line 947, in __init__
restore_signals, start_new_session)
File "/Users/kaswani/anaconda/envs/aws/lib/python3.5/subprocess.py", line 1551, in _execute_child
raise child_exception_type(errno_num, err_msg)
FileNotFoundError: [Errno 2] No such file or directory: 'aws'
I have not been able to debug it. Subprocess works just fine for basic commands like ls etc

Using, shell=True makes is work, i.e. subprocess.check_output(['aws','s3','cp','/Users/kaswani/tips.csv','s3://dplearn/'], shell=True)

run a file.gms from python script

I need to create a python script that runs a file gams (myfile.gms).
My file is in a folder F:\Otim\correct, so I was using a part of a code that I saw in this forum. I made:
import subprocess
subprocess.check_call(["F:\Otim\correct\myfile.gms"])
and I get an error:
Runtime error
Traceback (most recent call last):
File "<string>", line 80, in <module>
File "C:\Python27\ArcGIS10.2\Lib\subprocess.py", line 506, in check_call retcode = call(*popenargs, **kwargs)
File "C:\Python27\ArcGIS10.2\Lib\subprocess.py", line 493, in call return Popen(*popenargs, **kwargs).wait()
File "C:\Python27\ArcGIS10.2\Lib\subprocess.py", line 679, in __init__errread, errwrite)
File "C:\Python27\ArcGIS10.2\Lib\subprocess.py", line 896, in _execute_child
startupinfo)
WindowsError: [Error 193] %1 is not a valid Win32 application
Can someone help me please? Thanks

I've never used gams but after a quick look at www.gams.com it sounds like myfile.gms is not the file to be executed but the input file to be given as argument to the gams executable.
So you should try something like :
import subprocess
subprocess.check_call([r"C:\path\to\programs\GAMS.exe",r"F:\Otim\correct\myfile.gms"])
Notice : there is a GAMS python API which could give you a more portable solution.

UNIX Command within Python Script receiving an error. Script executes command does not

I have a python script. On top of the script "from subprocess import call". If I write "call(["whoami"])" in the script and I execute the Python script from the unix command line it works, my username returns. But if I run a proprietary command with arguments, "call(["mi_xx", "-s", "20141215","-e","20150121","-p",'TX%_XX%',"-f","test","-i","-x","-d"])"
I get the error below. I run the same command directly in unix and it works. I have searched up and down. The python environment in unix is fine.
Error
Traceback (most recent call last):
File "Mixx.py", line 44, in <module>
call(["mi_xx", "-s", "20141215","-e","20150121","-p",'TX%_XX%',"-f","test","-i","-x","-d"])
File "/bb/util/common/ActivePythonEE_2.6.2_32bit/lib/python2.6/subprocess.py", line 444, in call
return Popen(*popenargs, **kwargs).wait()
File "/bb/util/common/ActivePythonEE_2.6.2_32bit/lib/python2.6/subprocess.py", line 595, in __init__
errread, errwrite)
File "/bb/util/common/ActivePythonEE_2.6.2_32bit/lib/python2.6/subprocess.py", line 1092, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory"

Error from tshark and python

I am trying to execute this simple tshark command through python but I am not able to succeed and I don't understand the error
OS : Windows 7
Python 3.3
Code is
from subprocess import Popen
f = open("C:\\folder2\\test.txt","w")
Popen(["tshark" ,"-r","C:\\folder2\\fvido.pcap","-qz", "io,stat,0"],stdout=f)
and the error I get is
Traceback (most recent call last):
File "C:/Users/pc/Google Drive/Python/tshark1.py", line 6, in <module>
Popen(["tshark" ,"-r","C:\\folder2\\fvido.pcap","-qz", "io,stat,0"],stdout=f)
File "C:\Python33\lib\subprocess.py", line 820, in __init__
restore_signals, start_new_session)
File "C:\Python33\lib\subprocess.py", line 1112, in _execute_child
raise WindowsError(*e.args)
FileNotFoundError: [WinError 2] The system cannot find the file specified