Call rosrun from Matlab or alternative

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I already have a ros package with an executable inside it. From the terminal this is what I do to execute it:

$ source ~/catkin_ws/devel/setup.bash
$ rosrun my_package my_executable

This executable print some text on the shell:

Hello world

I want to call this commands in Matlab and import the printed text. I tried creating a shell script like this:

#!/bin/bash

source ~/catkin_ws/devel/setup.bash
rosrun my_package my_executable

and running it from Matlab in the following way:

[a,b] = system('~/./my_script')

but this is what I get:

[rosrun] Couldn't find executable named my_executable below /home/user/catkin_ws/src/my_package

The script works fine if called directly from the shell. How can I solve?