history -a

-a	append history lines from this session to the history file

history -a; ls -al ~/.bash_history

Save every executed command to: ~/.bash_history

export PROMPT_COMMAND='history -a'

Related

history -c
history -r

See also

• Bash history: history[ -a | -c | -r ], history --help, ~/.bash_history, HISTFILE, HISTSIZE, HISTTIMEFORMAT, HSTR