Read output of external command

Read output of external command

[Marco Patzer]

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Hi,

I need to read the standard output of an external command. This is
what I came up with:

\starttext
  \startluacode
    f = io.popen "ls"
    context(f:read "*a")
  \stopluacode
\stoptext

It works with luajittex, plain lua5.1 and lua5.2, but it fails with
a current luatex:

! LuaTeX error [string "\directlua "]:3: attempt to index global 'f' (a nil value)
stack traceback:
	[string "\directlua "]:3: in main chunk.

Why does this fail in luatex but works in lua5.2 ? What is the
correct way to obtain the output of a command?


Marco

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Re: Read output of external command

[Hans Hagen]

On 4/14/2013 12:06 PM, Marco Patzer wrote:
> Hi,
>
> I need to read the standard output of an external command. This is
> what I came up with:
>
> \starttext
>    \startluacode
>      f = io.popen "ls"
>      context(f:read "*a")
>    \stopluacode
> \stoptext

context(os.resultof("ls"))

> It works with luajittex, plain lua5.1 and lua5.2, but it fails with
> a current luatex:
>
> ! LuaTeX error [string "\directlua "]:3: attempt to index global 'f' (a nil value)
> stack traceback:
> 	[string "\directlua "]:3: in main chunk.
>
> Why does this fail in luatex but works in lua5.2 ? What is the
> correct way to obtain the output of a command?
>
>
> Marco
>
>
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
> archive  : http://foundry.supelec.fr/projects/contextrev/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________
>


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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________