Accessing Shell Variables

Accessing Shell Variables

[ahlan.marriott]

Hi,

I can access Windows, Linux and Osx environment variables using Ada.Environment_Variables.Value
However Linux and Osx also have Shell variables.
How can I access these?

Ahlan

Re: Accessing Shell Variables

[Victor Porton]

ahlan.marriott@gmail.com wrote:

> I can access Windows, Linux and Osx environment variables using
> Ada.Environment_Variables.Value However Linux and Osx also have Shell
> variables. How can I access these?

You cannot access a shell variable unless it is exported. Exported shell 
variable becomes and environment variable:

xxx=yyy
./my-program  # my-program cannot (at least in an easy way) access $xxx

export xxx=yyy
# or
xxx=yyy
export xxx
./my-program  # my-program cannot access xxx environment variable

-- 
Victor Porton - http://portonvictor.org

Re: Accessing Shell Variables

[Niklas Holsti]

On 16-12-28 20:19 , ahlan.marriott@gmail.com wrote:
> Hi,
>
> I can access Windows, Linux and Osx environment variables using Ada.Environment_Variables.Value
> However Linux and Osx also have Shell variables.
> How can I access these?

I think that's not possible, in any programming language. I have never 
heard of an OS service (API) that would access shell variables.

(BTW, I think some Windows shells also have shell variables.)

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
       .      @       .

Re: Accessing Shell Variables

[Simon Wright]

Victor Porton <porton@narod.ru> writes:

> ahlan.marriott@gmail.com wrote:
>
>> I can access Windows, Linux and Osx environment variables using
>> Ada.Environment_Variables.Value However Linux and Osx also have Shell
>> variables. How can I access these?
>
> You cannot access a shell variable unless it is exported. Exported shell 
> variable becomes and environment variable:
>
> xxx=yyy
> ./my-program  # my-program cannot (at least in an easy way) access $xxx
>
> export xxx=yyy
> # or
> xxx=yyy
> export xxx
> ./my-program  # my-program cannot access xxx environment variable

This variant is the one that *can* access the environment variable.

Re: Accessing Shell Variables

[Victor Porton]

Simon Wright wrote:

> Victor Porton <porton@narod.ru> writes:
> 
>> ahlan.marriott@gmail.com wrote:
>>
>>> I can access Windows, Linux and Osx environment variables using
>>> Ada.Environment_Variables.Value However Linux and Osx also have Shell
>>> variables. How can I access these?
>>
>> You cannot access a shell variable unless it is exported. Exported shell
>> variable becomes and environment variable:
>>
>> xxx=yyy
>> ./my-program  # my-program cannot (at least in an easy way) access $xxx
>>
>> export xxx=yyy
>> # or
>> xxx=yyy
>> export xxx
>> ./my-program  # my-program cannot access xxx environment variable
> 
> This variant is the one that *can* access the environment variable.

Yes, my typo.

-- 
Victor Porton - http://portonvictor.org

Re: Accessing Shell Variables

[ahlan.marriott]

On Wednesday, 28 December 2016 22:38:42 UTC+1, Victor Porton  wrote:
> Simon Wright wrote:
> 
> > Victor Porton <porton@narod.ru> writes:
> > 
> >> ahlan.marriott@gmail.com wrote:
> >>
> >>> I can access Windows, Linux and Osx environment variables using
> >>> Ada.Environment_Variables.Value However Linux and Osx also have Shell
> >>> variables. How can I access these?
> >>
> >> You cannot access a shell variable unless it is exported. Exported shell
> >> variable becomes and environment variable:
> >>
> >> xxx=yyy
> >> ./my-program  # my-program cannot (at least in an easy way) access $xxx
> >>
> >> export xxx=yyy
> >> # or
> >> xxx=yyy
> >> export xxx
> >> ./my-program  # my-program cannot access xxx environment variable
> > 
> > This variant is the one that *can* access the environment variable.
> 
> Yes, my typo.
> 
> -- 
> Victor Porton - http://portonvictor.org

Dear Victor,

Thank you for your reply.
I now understand (better) the difference between exported and non-exported shell variables.
Exporting the shell variable I wanted to access solves the problem.
Many thanks for answering my question ;-)
Best wishes,
Ahlan