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Re: initialisation bash variables

From: Patrick
Subject: Re: initialisation bash variables
Date: Wed, 28 Mar 2012 18:25:59 -0000
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20110617 Lightning/1.0b2 Thunderbird/3.1.11

On 17.08.2011 20:53, Stephane CHAZELAS wrote:
2011-08-17, 08:32(+02), Francky Leyn:
On 8/16/2011 10:53 PM, Stephane CHAZELAS wrote:
2) If VAR coincides with an environment variable, and in the
     script I change it value, is this then propagated to outside
     the script? Is the environment variable affected?

The environment is a list of strings (by convention of the format

In no circumstance are variable definitions in one process going
to affect the environment of other processes (an exception to
that is the "fish" shell)

Could it be that the two of you are not talking about the same thing?

Just for clarity: environment variables (henceforth "the environment") of a process are (is) inherited by its children.

Therefore, what *does* happen, is that if Stephane, as in 2), changes VAR in script, the change gets propagated to the scripts *child* processes.

$ X=1 bash             1*)
 $ echo $X
 $ X=2
 $ bash
  $ echo $X

But what does of course not happen, is that the change would get propagated to the *parent* process.

$ export X=1            2*)
$ echo $X
 $ bash
 $ X=2
 $ exit
$ echo $X

1*) X will exist only in the environment of the child process being started
2*) X will exist in the environment of the current process and will therefore be inherited and exist in the environment of its children as well

(What is the "fish" shell ???)

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