executing bash scripts sequentially in python

[rhitam30111985]

Hi all again . didnt know whether to put this in linux forum or here ... anyway.. i am trying to execute a sequence of bash commands from python .. but it doesnt seem to work :

[CODE=python]
#!/usr/bin/python
import os
os.system("myfi le=/home/pythonprac/commonwords")
os.system("echo $myfile")
[/CODE]

this is giving a blank output whereas it is supposed to display /home/pythonprac/commonwords

any idea where i am going wrong ?

thanks

[jlm699]

I believe that once the first os.system call ends any environment variables you may have created get cleaned up. Another solution would be to instead of executing individual commands write those commands to some temporary batch file. Then execute only the file. HTH

[fordie1000]

Hi all again . didnt know whether to put this in linux forum or here ... anyway.. i am trying to execute a sequence of bash commands from python .. but it doesnt seem to work :

[CODE=python]
#!/usr/bin/python
import os
os.system("myfi le=/home/pythonprac/commonwords")
os.system("echo $myfile")
[/CODE]

this is giving a blank output whereas it is supposed to display /home/pythonprac/commonwords

any idea where i am going wrong ?

thanks

Its best to use the 'popen' method ....

example of looking at whats in a text file on your system:

from os import popen

file = <some_file_on_your_system>
cmd = ('cat %s' % file)
ff = popen(cmd)
ff.readlines()

Hope this helps .... write back if you need further input

[Laharl]

You can also use a semicolon after a command to run a second command (or sequence of commands) on the shell. For example:
[CODE=python]
import os
os.system('ls; cd ..')
[/CODE] will run ls and then change to the parent directory.

[ghostdog74]

you don't have to call bash commands for what you are doing, reading a file?
use Python's own methods. this will ensure portability with your code

myfile="/home/myfile"
for lines in open(myfile): # equivalent of unix cat (or other tools for file reading)
    print lines

if you want to use ls, use Python's os.listdir, glob.glob(), etc
if you want to cd, use os.chdir() etc
Look at the os module (as well as sys) for such things.

[rhitam30111985]

you don't have to call bash commands for what you are doing, reading a file?
use Python's own methods. this will ensure portability with your code

myfile="/home/myfile"
for lines in open(myfile): # equivalent of unix cat (or other tools for file reading)
    print lines

if you want to use ls, use Python's os.listdir, glob.glob(), etc
if you want to cd, use os.chdir() etc
Look at the os module (as well as sys) for such things.

thanks a ton everyone . .. actually i was trying notjust to read a file but mail the contents of the file to any email address using the mail comamnd of bash . ... because for some reason SMTPlib was not working . anyhow ... . problem solved :-)

[fordie1000]

thanks a ton everyone . .. actually i was trying notjust to read a file but mail the contents of the file to any email address using the mail comamnd of bash . ... because for some reason SMTPlib was not working . anyhow ... . problem solved :-)

Would you mind posting your solution .... just for completeness ...

Thanks,