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Re: how to run shell command like "<<EOT .... EOT"

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  Re: how to run shell command like "<<EOT .... EOT" Kushal Kumaran <kushal.kumaran+python@gmail.com> - 2012-09-28 13:46 +0530

#30368 — Re: how to run shell command like "<<EOT .... EOT"

On Fri, Sep 28, 2012 at 1:15 PM, 叶佑群 <ye.youqun@eisoo.com> wrote:
> Hi, all,
>
>     I have the shell command like this:
>
> sfdisk -uM /dev/sdb << EOT
> ,1000,83
> ,,83
> EOT
>
>
>     I have tried subprocess.Popen, pexpect.spawn and os.popen, but none of
> these works, but when I type this shell command in shell, it is works fine.
> I wonder how to emulate this type of behavior in python , and if someone can
> figure out the reason why?
>
>     The sample code of subprocess.Popen is:
>
>     command = ["sfdisk", "-uM",  target, "<<EOT", "\r\n",
>                 ",", 1000, ",", "83", "\r\n",
>                 ",", ",", "83", "\r\n", "EOT", "\r\n"]
>
>     pobj = subprocess.Popen (command, bufsize=1, \
>                         stderr=subprocess.PIPE, stdout=subprocess.PIPE)
>
>     res = pobj.stderr.readline ()
>     if res is not None and pobj.returncode != 0:
>         observer.ShowProgress (u"对设备 %s 分区失败！" % target)
>         return False
>

The "<<EOT" syntax (called a here-document) just provides input to the
command.  If you use the communicate method, you can provide input as
an argument:

command = ["sfdisk", "-uM",  target ]
instructions = """
,1000,83
,,83
"""
pobj = subprocess.Popen(command, stdin=subprocess.PIPE,
stdout=subprocess.PIPE, stderr=subprocess.PIPE)
(output, errors) = pobj.communicate(instructions)

>     and pexpect code is:
>
>     child = pexpect.spawn ("sfdisk -uM /dev/sdb <<EOT")
>     child.sendline (....)
>     child.sendline (....)
>     child.sendline (....)
>
>     and os.popen like this:
>
>         os.popen ("sfdisk -uM /dev/sdb <<EOT\n,1000,83\n,,83\nEOT\n")
>
>     I tried "\r\n", and it doesn't work either.
>

-- 
regards,
kushal

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