This does not solve the issue. behave_different.sh has to behave different *all* the time *on every input*. Not just 99.999999% of the time. Imagine my_program

This does not solve the issue. behave_different.sh has to behave different *all* the time *on every input*. Not just 99.999999% of the time. Imagine my_program.sh says: echo "2022-02-26 10:30:00" and you run your version of behave_differently.sh at 10:29:59 on the 26/2. Then the output is the same.