topic Runtime Variable Value in Operating System - HP-UX

Runtime Variable Value

uform — Wed, 07 Mar 2007 19:55:30 GMT

Hi,

i have the following variables,

pri_running=0
var_running=pri_running

how can i set value of pri_running = 5
using the variable "var_running" ?

is it possible?

Re: Runtime Variable Value

Hein van den Heuvel — Wed, 07 Mar 2007 20:55:47 GMT

No that can not be done.

But why don't you try to explain the problem you are really trying to solve.

Also, in what context is that variable used?

I guess you intent a SHELL variable (which shell?)

But it could be C or AWK or whatever based on the limited description you provided.

In Perl things along those line can be done using REFERENCES.

Regards,
Hein.

Re: Runtime Variable Value

Bob E Campbell — Wed, 07 Mar 2007 23:11:25 GMT

Sure! That can be a handy trick at times. The secret is the "eval" built-in command:

$ var_running=pri_running
$ eval ${var_running}=5
$ echo $pri_running
5

The eval basically tells the shell to expand the variables before evaluating the expressions. To use a variable within an eval you would need to escape the $:

$ eval new_var=\$${var_running}
$ echo $new_var
5

I will warn you that self-modifying shell scripts can lead to madness (or at least hair loss).

Bob