Global bash varible not current shell or sub shell.

paulspedding · 05-30-2022, 07:28 AM

So I have tried export and declare and both don't seem to be setting a truly globalvar. I want to be able to access this varible from outside the script its set in.

How can I set a global varible so when the script has ended I can still access it from outside so other scripts can use it?

For instance I'm getting an Auth Token but I written smaller scripts with individual functions to use that Auth Token.

Thanks.

pan64 · 05-30-2022, 07:29 AM

would be nice to see exactly how did you set and what and also how did you try to use that later.

paulspedding · 05-30-2022, 07:43 AM

Quote:

Originally Posted by pan64

would be nice to see exactly how did you set and what and also how did you try to use that later.

#!/bin/bash
AUTH_TOKEN=$(this gets my auth token)
declare -g AUTH_TOKEN="$AUTH_TOKEN"

And then when I goto view it I use

echo "$AUTH_TOKEN"

I have tried the -x an -g and AFAIK the '-x' is the same as using:

export AUTH_TOKEN="$AUTH_TOKEN"

Isn't it? I also just tried using export but it didnt work either.

I was using to view the varible using both the following:

printenv
OR
declare -p

But I could never see them set. I did try to use `echo "$AUTH_TOKEN"` a few times but that yeilded empty results.

pan64 · 05-30-2022, 07:49 AM

still unclear, but some comments:

Quote:

Originally Posted by paulspedding

#!/bin/bash
AUTH_TOKEN=$(this gets my auth token)
declare -g AUTH_TOKEN="$AUTH_TOKEN"

Is this a script you executed? So it will set AUTH_TOKEN, but it will not be available in the parent shell anyway. You need to use source if you wish to modify the environment of the current shell.

Quote:

Originally Posted by paulspedding

And then when I goto view it I use

echo "$AUTH_TOKEN"

I have tried the -x an -g and AFAIK the '-x' is the same as using:

export AUTH_TOKEN="$AUTH_TOKEN"

Isn't it? I also just tried using export but it didnt work either.

I have no idea what do you mean by that. How did you try -x and -g ?

Quote:

Originally Posted by paulspedding

I was using to view the varible using both the following:

printenv
OR
declare -p

But I could never see them set. I did try to use `echo "$AUTH_TOKEN"` a few times but that yeilded empty results.

Again, I think you set the variable in a subshell, and checks the result in the current shell. But it is only a guess, I still don't understand what did you do.

teckk · 05-30-2022, 11:29 AM

Quote:

I want to be able to access this varible from outside the script its set in

one.sh

Code:

#!/usr/bin/bash

fred="Flintstone"
barney="Rubble"

wilma() {
    echo "Hello Wilma"
}

two.sh

Code:

#!/usr/bin/bash

source one.sh

echo "$fred"
echo "$barney"

wilma

Code:

bash ./two.sh
Flintstone
Rubble
Hello Wilma

teckk · 05-30-2022, 11:35 AM

three.sh

Code:

#!/usr/bin/bash

a=$(echo "Hello")
b=$(echo "World")

c() {
    echo "I like Linux"
}

Code:

source three.sh
echo "$a"
Hello
echo "$b"
World
c
I like Linux

teckk · 05-30-2022, 12:12 PM

four.sh

Code:

#!/usr/bin/bash

echo "expVar = $expVar"
echo "myVar = $myVar"

export expVar="Exported variable"
myVar="My variable"

Code:

bash ./four.sh
expVar = Exported variable
myVar =

echo "$expVar"
Exported variable

source four.sh
expVar = Exported variable
myVar = My variable

ondoho · 05-30-2022, 02:15 PM

^ That's one way to do it.
Another way to do it is to simply save the token to a (temporary) file.

A login shell can define global variables in the sense that all programs started under it will inherit its environment.

Defining a shell variable that somehow becomes valid outside of its scope is not possible.

MadeInGermany · 06-01-2022, 12:32 AM

In Unix-like systems there is no "globalvar".
Environment (including environment variables) is inherited by new forked processes (child processes) only. Not by processes that are outside.
You have to save/import it to/from a file. (Or use a DB service like dconf or polkit that also use a file for storage.)
In bash you can save environment-setting code to .bashrc then all new interactive bash processes (and their child processes) will get it.
A "globalvar"-like environment can be set for pid 1 (init or systemd) then all processes will inherit it. But inherit means copy; a change in the parent process will not arrive at the already forked child processes.