x = input("introduce el comando: ")
subprocess.call([x, ''], shell=True)
subprocess.call('cd ..', shell=True)

def back():
    path=os.getcwd()
    print path
    s=path.split('\')
    length=len(s)
    x=0

    while x<(length-1):
        if x==0:
            back_path=s[x]+"\"
        else:
            back_path=back_path+s[x]+"\"
        x+=1

    os.chdir(back_path)

os.chdir("..")

os.system(“el codigo en bash a ejecutar”)