[erlang-questions] [Erlang-Q] Why can not create a Mnesia schema directory indicated by a full path

[Ulf Wiger]

The application environment variables are a bit special, as they are not primarily intended to be set from the command line. They are normally defined either in the .app file or in the sys.config file.

The other command-line options, e.g. -pa and -pz, are more unix-like. :)

BR,
Ulf W

On 24 Apr 2011, at 19:22, Daniel Dormont wrote:

> As a relative newbie to Erlang but experienced Unix user, this was confusing to me at first. I'm very familiar with Unix shell escapes. What was surprising to me when I started working with Erlang was that command line options to Erlang modules require full-fledged Erlang terms: so if you want a string literal, such as in this case, the argument itself needs to include double quotes.
> 
> Dan
> 
> On Sun, Apr 24, 2011 at 8:00 AM, Ulf Wiger <ulf.wiger@REDACTED> wrote:
> 
> The issue is with quoting in the unix shell. Try:
> 
> erl -mnesia dir \"/home/myname/tmp/schemas\"
> 
> The reason why it worked with a single directory name was that it parsed as a valid atom, and the file module allows atoms as file names.
> 
> That is, for any environment variables given as -App Key Value  on the command line, Value will be parsed as an Erlang term. Anything with special meaning to the command shell needs to be escaped.
> 
> BR,
> Ulf W
> 
> On 24 Apr 2011, at 13:04, Barco You wrote:
> 
> > When I tried to indicate Mnesia schema directory with command: erl -mnesia dir "/home/myname/tmp/schemas", I got error while calling "mnesia:create_schema([node()|nodes()])" in erlang shell.
> >
> > But if I start erlang shell with just a string as the schema directory name such as " erl -mnesa dir location", I could correctly create schema in erlang shell.
> >
> > Seemingly Mnesia schema directory can not be indicated as a full path.
> >
> > {erts, "5.8"},
> > {kernel,"2.14"},
> > {stdlib,"1.17"}.
> >
> >
> > Best regards,
> > Barco
> > _______________________________________________
> > erlang-questions mailing list
> > erlang-questions@REDACTED
> > http://erlang.org/mailman/listinfo/erlang-questions
> 
> Ulf Wiger, CTO, Erlang Solutions, Ltd.
> http://erlang-solutions.com
> 
> 
> 
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Ulf Wiger, CTO, Erlang Solutions, Ltd.
http://erlang-solutions.com



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