Bash history finally done right

By default bash history is bad at sharing between terminals. I want:

Union of all terminals’ history in a new terminal
Each terminal to keep its own history while it is open
(optional) Type “sudo apt” and then press “up arrow” and it will search for everything starting with “sudo apt”
(optional) A file that keeps all of my history forever

And finally, via this post and the comment by Jo Liss, I’m happy:

# Insert into .bashrc

# Make sure you remove the existing history lines
# Usually:
###
#    HISTCONTROL=ignoreboth
#    shopt -s histappend
#    HISTSIZE=1000
#    HISTFILESIZE=2000
###

HISTSIZE=9000
HISTFILESIZE=$HISTSIZE
HISTCONTROL=ignorespace:ignoredups
_bash_history_sync() {
    builtin history -a
    HISTFILESIZE=$HISTSIZE
}
history() {
    _bash_history_sync
    builtin history "$@"
}
PROMPT_COMMAND=_bash_history_sync

if [[ "$-" =~ "i" ]] # Don't do this on non-interactive shells
then
    # Add MATLAB-style up-arrow, so if you type "ca[UP ARROW]" you'll get
    # completions for only things that start with "ca" like "cat abc.txt"
    bind '"\e[A":history-search-backward'
    bind '"\e[B":history-search-forward'
fi

# OPTIONAL: Keep a second history file forever
PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND ; }"'echo $$ $USER \
           "$(history 1)" >> ~/.bash_eternal_history'

09/4/18

Andrew J. Barry

Bash history finally done right