Unbuffered mode
Hi,
The man page for python says:
"-u Force stdin, stdout and stderr to be totally unbuffered."
However, when I try:
$ ssh localhost python -u
print 'hello, world'
[^D]
hello, world
$
Nothing happens until I send that EOF. I'm pretty sure it's not SSH
that's buffering because when I try:
$ ssh localhost bash
echo 'hello, world'
hello, world
[^D]
$
The 'hello, world' comes back immediately (I don't need to send the EOF).
I've also tried:
$ ssh localhost python -u
import sys
sys.stdout.write('hello, world\n')
sys.stdout.flush()
[^D]
hello, world
$
Again, nothing happens until I send the EOF. How can I get Python to
run over SSH unbuffered?
Thanks,
Hamish
--
http://mail.python.org/mailman/listinfo/python-list
Re: Unbuffered mode
Further to my query about trying to make Python run unbuffered, I have
discovered that a SyntaxError seems to cause Python to close its SSH
connection:
$ ssh localhost python -u
,
File "", line 1
,
^
SyntaxError: invalid syntax
$
Whereas a different sort of error (e.g. NameError) does not:
$ ssh localhost python -u
pront
[^D]
Traceback (most recent call last):
File "", line 1, in
NameError: name 'pront' is not defined
$
Can anyone tell me why?!
Thanks,
Hamish
On Feb 13, 2008 1:12 AM, Hamish Allan <[EMAIL PROTECTED]> wrote:
> Hi,
>
> The man page for python says:
>
> "-u Force stdin, stdout and stderr to be totally unbuffered."
>
> However, when I try:
>
> $ ssh localhost python -u
> print 'hello, world'
> [^D]
> hello, world
> $
>
> Nothing happens until I send that EOF. I'm pretty sure it's not SSH
> that's buffering because when I try:
>
> $ ssh localhost bash
> echo 'hello, world'
> hello, world
> [^D]
> $
>
> The 'hello, world' comes back immediately (I don't need to send the EOF).
>
> I've also tried:
>
> $ ssh localhost python -u
> import sys
> sys.stdout.write('hello, world\n')
> sys.stdout.flush()
> [^D]
> hello, world
> $
>
> Again, nothing happens until I send the EOF. How can I get Python to
> run over SSH unbuffered?
>
> Thanks,
> Hamish
>
--
http://mail.python.org/mailman/listinfo/python-list
Re: Unbuffered mode
Sorry to reply to myself again, but I think I now know the answer and
wish to post it for the archives.
Python run without '-i', if not sys.stdin.isatty(), expects to read a
whole script before doing anything else (presuming to be reading it
from a pipe). Therefore syntax errors are fatal, but otherwise nothing
is executed until EOF.
So the answer to my question is to run:
$ ssh localhost python -ui
Best wishes,
Hamish
On Feb 13, 2008 4:20 PM, Hamish Allan <[EMAIL PROTECTED]> wrote:
> Further to my query about trying to make Python run unbuffered, I have
> discovered that a SyntaxError seems to cause Python to close its SSH
> connection:
>
> $ ssh localhost python -u
> ,
> File "", line 1
> ,
> ^
> SyntaxError: invalid syntax
> $
>
> Whereas a different sort of error (e.g. NameError) does not:
>
> $ ssh localhost python -u
> pront
> [^D]
> Traceback (most recent call last):
> File "", line 1, in
> NameError: name 'pront' is not defined
> $
>
> Can anyone tell me why?!
>
> Thanks,
> Hamish
>
>
> On Feb 13, 2008 1:12 AM, Hamish Allan <[EMAIL PROTECTED]> wrote:
> > Hi,
> >
> > The man page for python says:
> >
> > "-u Force stdin, stdout and stderr to be totally unbuffered."
> >
> > However, when I try:
> >
> > $ ssh localhost python -u
> > print 'hello, world'
> > [^D]
> > hello, world
> > $
> >
> > Nothing happens until I send that EOF. I'm pretty sure it's not SSH
> > that's buffering because when I try:
> >
> > $ ssh localhost bash
> > echo 'hello, world'
> > hello, world
> > [^D]
> > $
> >
> > The 'hello, world' comes back immediately (I don't need to send the EOF).
> >
> > I've also tried:
> >
> > $ ssh localhost python -u
> > import sys
> > sys.stdout.write('hello, world\n')
> > sys.stdout.flush()
> > [^D]
> > hello, world
> > $
> >
> > Again, nothing happens until I send the EOF. How can I get Python to
> > run over SSH unbuffered?
> >
> > Thanks,
> > Hamish
> >
>
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http://mail.python.org/mailman/listinfo/python-list
