#How to invoke normal bash commands from python?
# For that you need to import a module called os.
import os
os.system('ls -l') # prints the contents
print os.system('ls -l') # prints contents + return code 
error = os.system('ls -l tmp')
#exit code is stored in error
if error == 0:
	print 'found'
else:
	print 'not found'