bash save history without exit

Question

in linux ubuntu bash terminal. is there any way to save bash history without writing exit? i've set the config to "HISTCONTROL=erasedups"

which in my opinion works better than ignoredups.

anyways for some reason it wont save the last few commands in the bash terminal unless i type in "exit". I'm used to just click the cross on the terminal window, so i'm always annoyed that the last commands were not saved when i relogin.

reminder: http://www.thegeekstuff.com/2008/08/15-examples-to-master-linux-command-line-history/#more-130

Answer 1

There is a way to save all your bash history to a separate file, but if you are trying to use the history mechanism and for some reason it is not saving all of your history, that is a different issue.

To save all your history to a separate file, always, no matter what happens to the terminal

A script provided here does the trick.

# don't put duplicate lines in the history. See bash(1) for more options
# ... and ignore same sucessive entries.
export HISTCONTROL=ignoreboth

# set the time format for the history file.
export HISTTIMEFORMAT="%Y.%m.%d %H:%M:%S "

# If this is an xterm set the title to user@host:dir
case "$TERM" in
  xterm*|rxvt*)
  # Show the currently running command in the terminal title:
  # http://www.davidpashley.com/articles/xterm-titles-with-bash.html
  show_command_in_title_bar()
  {
    case "$BASH_COMMAND" in
      *\033]0*)
      # The command is trying to set the title bar as well;
      # this is most likely the execution of $PROMPT_COMMAND.
      # In any case nested escapes confuse the terminal, so don't
      # output them.
      ;;
      *)
      if test ! "$BASH_COMMAND" = "log_bash_eternal_history"
      then
        echo -ne "\033]0;$(history 1 | sed 's/^ *[0-9]* *//') :: ${PWD} :: ${USER}@${HOSTNAME}\007"
      fi
      ;;
    esac
  }
  trap show_command_in_title_bar DEBUG
  ;;
  *)
  ;;
esac

log_bash_eternal_history()
{
  local rc=$?
  [[ $(history 1) =~ ^\ *[0-9]+\ +([^\ ]+\ [^\ ]+)\ +(.*)$ ]]
  local date_part="${BASH_REMATCH[1]}"
  local command_part="${BASH_REMATCH[2]}"
  if [ "$command_part" != "$ETERNAL_HISTORY_LAST" -a "$command_part" != "ls" -a "$command_part" != "ll" ]
  then
    echo $date_part $HOSTNAME $rc "$command_part" >> ~/.bash_eternal_history
    export ETERNAL_HISTORY_LAST="$command_part"
  fi
}

PROMPT_COMMAND="log_bash_eternal_history"

To tell the history command "Save now!" when clicking the X on a virtual terminal window

First what you have to understand is, what mechanism does your virtual terminal emulator use to kill the bash process when it exits? -- This will depend on what exact terminal emulator you are using.

There are a few options, and all of them involve UNIX signals.

• SIGTERM, SIGINT, SIGQUIT: The default behavior when Bash receives one of these signals in interactive mode is to ignore it, so it's probably not that.

• SIGHUP: This signal ordinarily causes Bash to terminate gracefully and do cleanup, but I'm not sure if that "cleanup" involves saving the history file. It probably doesn't.

• SIGKILL, SIGSTOP: It is impossible for Bash as a userspace process to ignore these signals. The kernel can forcibly kill or stop the process at any time using these signals. If your VT emulator is sending one of these, we can't trap it and do something before exiting, so you're out of luck.

A few references: ServerFault question 337123

Unix question 6332

Using History Interactively in the GNU Bash manual