Save and reload history after each command so that history works reguardless of where you are

[NonlinearFruit]

https://unix.stackexchange.com/a/1292/194972

[NonlinearFruit]

# Avoid duplicates
HISTCONTROL=ignoredups:erasedups
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend

# After each command, append to the history file and reread it
PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND$'\n'}history -a; history -c; history -r"

[NonlinearFruit]

Downside pointed out by a friend is that this method would break the 'up arrow':

• Terminal A: echo Hello
• Terminal B: ls
• Terminal A: [up arrow]
  • Displays ls

[NonlinearFruit]

Maybe what I want is 'every shell has it's own history' and the history is appended to the global history on exit

• Shell A has History A
• When reverse searching history, search History A plus global history
• When exiting Shell A, append History A to global history
• Add ability to search global history plus all local histories (some times it is hard to remember which shell did the command)

[NonlinearFruit]

Here is my idea:

• Make a file .bash_history_all which will contain all of .bash_history plus the current shell's in memory history
• Make an alias ghistory='HISTFILE=~/.bash_history history'
• Change CTRL+R to use .bash_history_all
• Update prompt to dump in memory history into .bash_history_all
  • PROMPT_COMMAND='history -a'? (stackoverflow)

This way we have:

• Up arrow works intuitively
• Search commands searches all commands (across open shells)