How to set program name in Python? ($0 in Perl)

[Swaroop C H]

Hi,

Is there a way to set the program name in Python, similar to $0 in
Perl?
[color=blue]
>From `man perlvar`:[/color]

$0 Contains the name of the program being executed. On some oper-
ating systems assigning to "$0" modifies the argument
area that
the ps program sees. This is more useful as a way of
indicat-
ing the current program state than it is for hiding the
program
you're running. (Mnemonic: same as sh and ksh.)



Thanks!
Swaroop

https://www.swaroopch.info

[Steve Holden]

Re: How to set program name in Python? ($0 in Perl)

Swaroop C H wrote:[color=blue]
> Hi,
>
> Is there a way to set the program name in Python, similar to $0 in
> Perl?
>[color=green]
>>From `man perlvar`:[/color]
>
> $0 Contains the name of the program being executed. On some oper-
> ating systems assigning to "$0" modifies the argument
> area that
> the ps program sees. This is more useful as a way of
> indicat-
> ing the current program state than it is for hiding the
> program
> you're running. (Mnemonic: same as sh and ksh.)
>
>
>
> Thanks!
> Swaroop
> www.swaroopch.info
>[/color]

import sys
print sys.argv[0]

regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.python.org/pycon/

[Fredrik Lundh]

Re: How to set program name in Python? ($0 in Perl)

Steve Holden wrote:
[color=blue][color=green]
> > Is there a way to set the program name in Python, similar to $0 in
> > Perl?
> >[color=darkred]
> >>From `man perlvar`:[/color]
> >
> > $0 Contains the name of the program being executed. On some oper-
> > ating systems assigning to "$0" modifies the argument
> > area that
> > the ps program sees. This is more useful as a way of
> > indicat-
> > ing the current program state than it is for hiding the
> > program
> > you're running. (Mnemonic: same as sh and ksh.)[/color][/color]
[color=blue]
> import sys
> print sys.argv[0][/color]

that *gets* the name, but assigning to sys.argv[0] doesn't *set* it (afaik).

setting the name involves overwriting the C level argv array, several large
buckets of worms, and huge portability issues, and is thus better left to non-
standard extensions.

</F>

[Steve Holden]

Re: How to set program name in Python? ($0 in Perl)

Fredrik Lundh wrote:[color=blue]
> Steve Holden wrote:
>
>[color=green][color=darkred]
>>>Is there a way to set the program name in Python, similar to $0 in
>>>Perl?
>>>
>>>>From `man perlvar`:
>>>
>>>$0 Contains the name of the program being executed. On some oper-
>>> ating systems assigning to "$0" modifies the argument
>>>area that
>>> the ps program sees. This is more useful as a way of
>>>indicat-
>>> ing the current program state than it is for hiding the
>>>program
>>> you're running. (Mnemonic: same as sh and ksh.)[/color][/color]
>
>[color=green]
>>import sys
>>print sys.argv[0][/color]
>
>
> that *gets* the name, but assigning to sys.argv[0] doesn't *set* it (afaik).
>
> setting the name involves overwriting the C level argv array, several large
> buckets of worms, and huge portability issues, and is thus better left to non-
> standard extensions.
>[/color]
Indeed. My bad.

regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.python.org/pycon/

[Swaroop C H]

Re: How to set program name in Python? ($0 in Perl)

Thanks Fredrik for the info.

It was not a must-have, I was just curious if it was possible.

Thanks,
Swaroop

https://www.SwaroopCH.info

[Fredrik Lundh]

Re: How to set program name in Python? ($0 in Perl)

Swaroop C H wrote:
[color=blue]
> Thanks Fredrik for the info.
>
> It was not a must-have, I was just curious if it was possible.[/color]

it should be noted that some systems have a setproctitle() function, but the design
of that API comes with its own can of quality worms:

http://www.cert.org/advisories/CA-2000-13.html

</F>

[Bengt Richter]

Re: How to set program name in Python? ($0 in Perl)

On Thu, 10 Nov 2005 08:06:27 +0100, "Fredrik Lundh" <fredrik@python ware.com> wrote:
[color=blue]
>Steve Holden wrote:
>[color=green][color=darkred]
>> > Is there a way to set the program name in Python, similar to $0 in
>> > Perl?
>> >
>> >>From `man perlvar`:
>> >
>> > $0 Contains the name of the program being executed. On some oper-
>> > ating systems assigning to "$0" modifies the argument
>> > area that
>> > the ps program sees. This is more useful as a way of
>> > indicat-
>> > ing the current program state than it is for hiding the
>> > program
>> > you're running. (Mnemonic: same as sh and ksh.)[/color][/color]
>[color=green]
>> import sys
>> print sys.argv[0][/color]
>
>that *gets* the name, but assigning to sys.argv[0] doesn't *set* it (afaik).
>
>setting the name involves overwriting the C level argv array, several large
>buckets of worms, and huge portability issues, and is thus better left to non-
>standard extensions.
>[/color]
OTOH, if the intent is just to set a value for subsequent getting by way of
sys.argv[0], isn't sys.argv an ordinary list?
[color=blue][color=green][color=darkred]
>>> import sys
>>> sys.argv[0][/color][/color][/color]
''[color=blue][color=green][color=darkred]
>>> sys.argv[0] = '<interactive> '
>>> sys.argv[0][/color][/color][/color]
'<interactive> '
[color=blue][color=green][color=darkred]
>>> type(sys.argv)[/color][/color][/color]
<type 'list'>

Regards,
Bengt Richter

[Fredrik Lundh]

Re: How to set program name in Python? ($0 in Perl)

Bengt Richter wrote:
[color=blue][color=green][color=darkred]
> >> > Is there a way to set the program name in Python, similar to $0 in
> >> > Perl?
> >> >
> >> >>From `man perlvar`:
> >> >
> >> > $0 Contains the name of the program being executed. On some oper-
> >> > ating systems assigning to "$0" modifies the argument area that
> >> > the ps program sees. This is more useful as a way of indicat-
> >> > ing the current program state than it is for hiding the program
> >> > you're running. (Mnemonic: same as sh and ksh.)[/color][/color][/color]
[color=blue]
> OTOH, if the intent is just to set a value for subsequent getting by way of
> sys.argv[0], isn't sys.argv an ordinary list?
>[color=green][color=darkred]
> >>> import sys
> >>> sys.argv[0][/color][/color]
> ''[color=green][color=darkred]
> >>> sys.argv[0] = '<interactive> '
> >>> sys.argv[0][/color][/color]
> '<interactive> '
>[color=green][color=darkred]
> >>> type(sys.argv)[/color][/color]
> <type 'list'>[/color]

given that Swaroop has written a nice book about Python, I somehow
suspect that he knows how sys.argv works:

http://tinyurl.com/9s7bz

or are you saying that "ps" looks inside sys.argv on your machine?

</F>

[Bengt Richter]

Re: How to set program name in Python? ($0 in Perl)

On Thu, 10 Nov 2005 23:29:28 +0100, "Fredrik Lundh" <fredrik@python ware.com> wrote:
[color=blue]
>Bengt Richter wrote:
>[color=green][color=darkred]
>> >> > Is there a way to set the program name in Python, similar to $0 in
>> >> > Perl?
>> >> >
>> >> >>From `man perlvar`:
>> >> >
>> >> > $0 Contains the name of the program being executed. On some oper-
>> >> > ating systems assigning to "$0" modifies the argument area that
>> >> > the ps program sees. This is more useful as a way of indicat-
>> >> > ing the current program state than it is for hiding the program
>> >> > you're running. (Mnemonic: same as sh and ksh.)[/color][/color]
>[color=green]
>> OTOH, if the intent is just to set a value for subsequent getting by way of
>> sys.argv[0], isn't sys.argv an ordinary list?
>>[color=darkred]
>> >>> import sys
>> >>> sys.argv[0][/color]
>> ''[color=darkred]
>> >>> sys.argv[0] = '<interactive> '
>> >>> sys.argv[0][/color]
>> '<interactive> '
>>[color=darkred]
>> >>> type(sys.argv)[/color]
>> <type 'list'>[/color]
>
>given that Swaroop has written a nice book about Python, I somehow
>suspect that he knows how sys.argv works:
>
> http://tinyurl.com/9s7bz
>[/color]
Sorry, I wasn't familiar with that (or Swaroop ;-)
[color=blue]
>or are you saying that "ps" looks inside sys.argv on your machine?
>[/color]
Nope. Hm, I wrote a little C a few years ago utility that prints a date-time prefix
and the raw command line string but skipping arg 0. It uses win32's GetCommandLine,
which returns a string pointer.

[18:58] C:\pywk\clp>log line arg1 arg2 note preserved spaces.
20051110 18:58:24 arg1 arg2 note preserved spaces.

Maybe ctypes could be used to get the pointer and carefully poke in a mod. But I don't know if
the cmd line string is within a static fixed size array so you could lengthen it, or what.
Or have they opened the source for that? Anyway, I don't know if that is where ps (pstat on my NT box)
looks. Not handy to experiment ATM ;-)

Regards,
Bengt Richter

[jmdeschamps@gmail.com]

Re: How to set program name in Python? ($0 in Perl)

This is not directly what the OP wanted in regards to Perl, but to see
what one could do if one needed to change the name of the running
program, I wrote this:
## START PROGRAM
import sys
import os.path
import shutil
import os

def testChangingNam e(appname):
hopedfornameis = appname
mylongnameis = sys.argv[0]
mynameis = os.path.basenam e(mylongnameis)
basenameis = os.path.dirname (mylongnameis)
if mynameis != hopedfornameis:
shutil.copyfile (mynameis, basenameis+"/"+hopedfornamei s)

os.spawnv(os.P_ NOWAIT,"c:/python23/python.exe",('c :/python23/python.exe',hop edfornameis))
sys.exit()

if __name__ == "__main__":
print sys.argv[0]
testChangingNam e("testNameIsCh anged.py")
s=raw_input("Al l's well!")
s=raw_input("No w do something useful")

## END PROGRAM

Since I don't know the circumstance in which the OP wanted to change
the name, I really don't know what caveats one should look out for
here.
I would be curious to know when such a function could come in handy.

Jean-Marc