Simple question for all of you python gurus

[Sean Berry]

I am writing a little script to grep through a really long list of files and
look for a certain phrase.

I wanted to do something like this.

li = os.popen("/usr/bin/grep -i %s /home/%s/.tmda/pending" %(phrase,userid )
lis = li.readlines()
blah blah blah...

but even if I run this from the command line I get an error saying the
argument list is too long.

However, if I cd to /home/userid/.tmda/pending and then run the grep from
within the directory... it works great.

so I tried to do something like this
os.system("cd /home/%s/.tmda/pending" %userid)
li = os.popen("/usr/bin/grep -i %s" %phase)
lis = lis.readlines()

But since cd is a shell command, it does not seem to work either.

How can I do this?
Thanks in advance for answering this seemingly easy question.

[Diez B. Roggisch]

Re: Simple question for all of you python gurus

> How can I do this?[color=blue]
> Thanks in advance for answering this seemingly easy question.[/color]

You're code might work if you use os.chdir to change the current working
directory.

Another that works on the command-line (and thus for your script) is to use
xargs with -l<num>, e.g.:

find / | xargs -l 10 grep -i foo

xargs then will invoke grep in batches of ten.



--
Regards,

Diez B. Roggisch

[Cameron Laird]

Re: Simple question for all of you python gurus

In article <NYu%b.12366$qL 1.145@fed1read0 2>,
Sean Berry <sean_berry@cox .net> wrote:

[Sean Berry]

Re: Simple question for all of you python gurus

Thanks to you both.

os.chdir ... I knew it was something simple. Sorry for the wasted
bandwidth.

Cameron Laird <claird@lairds. com> wrote in message
news:103svepnqo vuk5e@corp.supe rnews.com...[color=blue]
> In article <NYu%b.12366$qL 1.145@fed1read0 2>,
> Sean Berry <sean_berry@cox .net> wrote:
> .
> .
> .[color=green]
> >so I tried to do something like this
> >os.system("c d /home/%s/.tmda/pending" %userid)
> >li = os.popen("/usr/bin/grep -i %s" %phase)
> >lis = lis.readlines()
> >
> >But since cd is a shell command, it does not seem to work either.
> >
> >How can I do this?[/color]
> .
> .
> .
> import os
>
> os.chdir("/home/%s/.tmda/pending" % userid)
> li = os.popen(...
> --
>
> Cameron Laird <claird@phaseit .net>
> Business: http://www.Phaseit.net[/color]

[Jeremy Sanders]

Re: Simple question for all of you python gurus

On Thu, 26 Feb 2004 23:14:33 +0000, Cameron Laird wrote:
[color=blue]
> os.chdir("/home/%s/.tmda/pending" % userid)
> li = os.popen(...[/color]

Wouldn't something like this also work?

li = os.popen('/bin/sh -c "cd /home/%s; /usr/bin/grep -i %s blah"')

This has the advantage that the current directory of the Python program
doesn't change.

Jeremy

[Cameron Laird]

Re: Simple question for all of you python gurus

In article <pan.2004.02.27 .10.23.57.12660 0@jeremysanders .net>,
Jeremy Sanders <jeremy+plusnew s@jeremysanders .net> wrote:[color=blue]
>On Thu, 26 Feb 2004 23:14:33 +0000, Cameron Laird wrote:
>[color=green]
>> os.chdir("/home/%s/.tmda/pending" % userid)
>> li = os.popen(...[/color]
>
>Wouldn't something like this also work?
>
>li = os.popen('/bin/sh -c "cd /home/%s; /usr/bin/grep -i %s blah"')
>
>This has the advantage that the current directory of the Python program
>doesn't change.[/color]