install.sh ran as root and created /tmp/aic8800d80_install.log with mode
666 at a fixed, predictable path. Root writing to a fixed name in /tmp is
open to symlink races (mitigated, not removed, by fs.protected_symlinks),
and a world-writable log lets any local user alter what an administrator
later reads.
The log now lives at /var/log/aic8800-install.log, is created with mode
0644 only after the root check, and failed writes before that point are
silenced instead of printing redirection errors. diagnostic_build.sh
reads the new path and falls back to the old one for logs left by
earlier installers.
The final instructions printed commands with plain echo, so the colour
variables appeared as literal "\033[0;34m" text. Use echo -e for those
lines, as the rest of the script already does.
Make diagnose_bt.sh executable like the other scripts, so it runs without
the separate chmod step.
Resolve the shellcheck warnings in install.sh: declare and assign
separately (SC2155), drop an unused loop variable (SC2034) and a useless
cat (SC2002), and mark the ERR trap handler as indirectly invoked
(SC2317). No behaviour change.
rtk94