Bash practices for handling exit codes (Reference: https://stackoverflow.com/a/45817972/4449273)

exit_codes.sh

#!/bin/bash

# In case of simple logging
complex_command && echo "Success" >> log.txt || echo "Failure" >> log.txt

# In case of complex command chaining
complex_command
if [ $? -ne 0]; then
  success_complex_command  # this command could fail as well 
  # its exit code can be treated in a nested manner by testing $? again
else
  failure_complex_command
fi