save-entropy: Fix the guard to avoid non-digits

[jlduran]

Summary

Fix a guard that prevents a comparison with a non-digit to fail the
script.

Test Plan

touch ${entropy_dir}/saved-entropy.    # SKIP
touch ${entropy_dir}/saved-entropyx    # SKIP
touch ${entropy_dir}/saved-entropy.\*  # THE CURRENT CHECK (SKIP)
touch ${entropy_dir}/saved-entropy.0   # PASS
touch ${entropy_dir}/saved-entropy.01  # PASS
touch ${entropy_dir}/saved-entropy.1a  # SKIP
touch ${entropy_dir}/saved-entropy.9   # PASS
touch ${entropy_dir}/saved-entropy.a   # SKIP

[jlduran]

While studying for D47502, I stumbled upon the save-entropy.sh script. This part of the script seems wrong to me.
What I can infer is that this tries to guard against failing a comparison with a non-digit on the next line, by checking that whatever comes after saved-entropy. is a digit. Currently it is only checking for saved-entropy.\* (a literal *).
I don't know whom to ask for review. This change is low-priority, as it only verifies correctness, only root can write to the $entropy_dir.
Thank you!

[des]

libexec/save-entropy/save-entropy.sh

71

72

drop this

[jlduran]

libexec/save-entropy/save-entropy.sh

72

Your suggestion would fail if there is a file named saved-entropy.1a, for example ([: 1a: bad number).

[des]

libexec/save-entropy/save-entropy.sh

72

You'll have to weigh how likely that is to happen up against the cost of the added complexity required to deal with the situation.