Why doesn't getenv work on MAC OS X?

I was trying to get environment variables that I know exist but it returns empty arrays...is that normal?

hello =

    00 empty char array

res =

    00 empty char array

>>

from running

    hello = getenv('hello')
    res = getenv('SYSTEMROOT')

----

These are the scripts I am exactly running:

#!/bin/bash
alias matlab='/Applications/MATLAB_R2017a.app/bin/matlab -nodesktop -nosplash'

hello=hellohello
echo $hello
matlab -nodesktop -nosplash -nojvm -r "test_sh"

which runs the following:

clear;
%SLURM_JOBID = getenv('SLURM_JOBID')
%SLURM_ARRAY_TASK_ID = getenv('SLURM_ARRAY_TASK_ID')
hello = getenv('hello')
res = getenv('SYSTEMROOT')
PATH = getenv('PATH')

[Jos (10584)]

How do you know they exist? Apparently Matlab cannot find them. I have no problem on my Mac.

[Brando Miranda]

what I do is run a bash script then in the bash script itself I create and echo the env variable. So it exists for sure at least in the bash script. The I run the matlab script and they are nowhere to be found:

#!/bin/bash
alias matlab='/Applications/MATLAB_R2017a.app/bin/matlab -nodesktop -nosplash'

hello=hellohello
echo $hello
matlab -nodesktop -nosplash -nojvm -r "test_sh"

which runs:

clear;
%SLURM_JOBID = getenv('SLURM_JOBID')
%SLURM_ARRAY_TASK_ID = getenv('SLURM_ARRAY_TASK_ID')
hello = getenv('hello')
res = getenv('SYSTEMROOT')
PATH = getenv('PATH')

Answer 1

[Greg]

One article I read indicates you need to call

export hello

To actually set hello as an environment variable. Otherwise, hello only exists as a "shell variable." I'm definitely not a MAC wizard, so I have no clue if that's correct, just a quick Google search.