better_history.sh

# Custom history configuration
# Run script using:
# chmod u+x better_history.sh
# sudo su
# ./better_history.sh

echo ">>> Starting"
echo ">>> Loading configuration into /etc/bash.bashrc"
echo "HISTTIMEFORMAT='%F %T '" >> /etc/bash.bashrc
echo 'HISTFILESIZE=-1' >> /etc/bash.bashrc
echo 'HISTSIZE=-1' >> /etc/bash.bashrc
echo 'HISTCONTROL=ignoredups' >> /etc/bash.bashrc
echo 'HISTIGNORE=?:??' >> /etc/bash.bashrc
echo '# append to history, dont overwrite it' >> /etc/bash.bashrc
echo 'shopt -s histappend' >> /etc/bash.bashrc
echo '# attempt to save all lines of a multiple-line command in the same history entry' >> /etc/bash.bashrc
echo 'shopt -s cmdhist' >> /etc/bash.bashrc
echo '# save multi-line commands to the history with embedded newlines' >> /etc/bash.bashrc
echo 'shopt -s lithist' >> /etc/bash.bashrc
echo '# After each command, append to the history file and reread it' >> /etc/bash.bashrc
echo 'export PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$"\n"}history -a; history -c; history -r"' >> /etc/bash.bashrc

# Reload BASH for settings to take effect
echo ">>> Reloading BASH"
exec "$BASH"

echo ">>> Finished. Exiting."

Thanks for your blog post on bash history, and this script.

I'm still evaluating, but as of now, I wonder if your PROMPT_COMMAND is, uh... "a universally good thing"?

PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$"\n"}history -a; history -c; history -r"

Here's why: At times, I keep 2 or 3 SSH sessions open to hosts where I use bash as the interactive shell. I use these sessions for different purposes; e.g. one session may be used for script development, while another is used for support... man whatever & that sort of thing. Working this way, a unique session history has advantages. For me, PROMPT_COMMAND='history -a' is all I really want while I am working - I don't need a "merged" history from other sessions. This of course is personal; it depends on one's use case or workflow.

So that's it - just a comment with another point of view.

The blog is not working anymore, but Wayback Machine has a copy: https://web.archive.org/web/20210520231125/https://www.thomaslaurenson.com/blog/2018-07-02/better-bash-history/