return a value to shell script

[devi thapa]

Hi,

I am executing a python script in a shell script. The python script
actually returns a value.
So, can I get the return value in a shell script? If yes, then help me out.

Regards,
Devi

[Tom Wright]

Re: return a value to shell script

devi thapa wrote:

I am executing a python script in a shell script. The python script
actually returns a value.
So, can I get the return value in a shell script? If yes, then help me
out.

Yes. The variable $? should be bound to the return value of the last
foreground program to exit. The python script can return a value using
sys.exit(value)

HTH


--
I'm at CAMbridge, not SPAMbridge

[D'Arcy J.M. Cain]

Re: return a value to shell script

On Wed, 12 Nov 2008 13:09:21 +0000
Tom Wright <tew24@spam.ac. ukwrote:

devi thapa wrote:

I am executing a python script in a shell script. The python script
actually returns a value.
So, can I get the return value in a shell script? If yes, then help me
out.

>
Yes. The variable $? should be bound to the return value of the last
foreground program to exit. The python script can return a value using
sys.exit(value)

That may be true for some shells but not all. The correct answer to
the OP's question is - check the documentation for your specific shell
or ask on a group dedicated to the shell you are using.

--
D'Arcy J.M. Cain <darcy@druid.ne t | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.

[Jeff McNeil]

Re: return a value to shell script

On Nov 12, 8:19 am, "D'Arcy J.M. Cain" <da...@druid.ne twrote:

On Wed, 12 Nov 2008 13:09:21 +0000
>
Tom Wright <te...@spam.ac. ukwrote:

devi thapa wrote:

I am executing a python script in a shell script. The python script
actually returns a value.
So, can I get the return value in a shell script? If yes, then help me
out.

>

Yes. The variable $? should be bound to the return value of the last
foreground program to exit. The python script can return a value using
sys.exit(value)

>
That may be true for some shells but not all. The correct answer to
the OP's question is - check the documentation for your specific shell
or ask on a group dedicated to the shell you are using.
>
--
D'Arcy J.M. Cain <da...@druid.ne t | Democracy is three wolveshttp://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.

It depends on what your exit value is, though. While your shell will
probably provide some method for determining the exit status of your
process, you're limited to a range of 0-255. If, for example, you've
got your Python script exiting with the number of rows in a database,
you'll simply overflow.

[jeff@marvin ~]$ python -c 'import sys; sys.exit(0)' ; echo $?
0
[jeff@marvin ~]$ python -c 'import sys; sys.exit(1)' ; echo $?
1
[jeff@marvin ~]$ python -c 'import sys; sys.exit(255)' ; echo $?
255
[jeff@marvin ~]$ python -c 'import sys; sys.exit(256)' ; echo $?
0

Depending on what you're doing, printing from your Python program and
capturing standard out might be a better approach.

HTH,

Jeff

[Grant Edwards]

Re: return a value to shell script

On 2008-11-12, devi thapa <devi.thapa@gma il.comwrote:

I am executing a python script in a shell script. The python
script actually returns a value. So, can I get the return
value in a shell script? If yes, then help me out.

There are two ways to "return" something to a shell script.

1) To return a success/fail indication, use sys.exit(n). n==0
means success, n!=0 means fail.

2) To return the end value of an operation or computation to a
shell script, you write it to stdout as an ascii string.

--
Grant Edwards grante Yow! I'm wet! I'm wild!
at
visi.com