Note if it doesn't complete or if any sort of warning or error messages are displayed. To see if it encounters any problems, instead of closing the terminal exit the shell manually with exit (or Control-D). When you exit the shell, this code will save new commands to the terminal's history in ~/.bash_sessions. If you install an EXIT signal handler with trap be sure to do something similar (or call shell_session_update from your handler if you can't figure out how to concatenate to the previous value-it's a little involved).

If you customize PROMPT_COMMAND be sure to concatenate to the previous value so you don't wipe out the system-supplied command: PROMPT_COMMAND='$your_code_here' Read the comments in /etc/bashrc_Apple_Terminal for an explanation of how it manages per-terminal command histories and how to customize it. Starting in OS X 10.11 El Capitan, the system-installed script /etc/bashrc_Apple_Terminal coordinates with Terminal in order to save/restore separate command histories for each terminal restored for Resume.

Mac terminal commands history