This is handy, but if you just want the ability to see when you ran a previous command you can add

    export HISTTIMEFORMAT="%d/%m/%y %T "

to your .bashrc and then

    history

will show the date and time before each command that was run.

I'm sure most know this but if anyone thinks this is a way of doing forensics, keep in mind it can be easily skipped over by doing a non-standard logout, like "kill -9 $$" or if a remote ssh connection gets cut for whatever reason. The command history for a session won't get written until logout by default. A workaround such as forcing each entry to be written to a log file will have to be done to have better assurance of true history.

> forcing each entry to be written to a log file

When I last needed it ~2011, there was a small and simple tool called libsnoopy for that.

Emphasis on "log file" though, the "history file" is a different use case, fundamentally unfit for forensics.

I've had this for a while and I noticed at least two problems on my mac:

1) It made the history command run much, much slower (I have HISTSIZE=100000)

2) Dates tend to reset to a uniform but meaningless value. I think it's related to OS reboots.

Excellent point. Seeing when a command in the history list was run is very useful.

My preference is just for a date in the history, rather than date and time. I find that when I'm searching history, date is usually granular enough for me, so I can omit the time and save a little bit of screen real estate.

I had no idea! I was about to try out the linked article, but this is all I really need. Excellent!

I recommend using both approaches together.

With an updating prompt, you can see when a command ran without having to type 'history'.

And adding a date/time stamp to history is very useful when you need to go back further - hours, days or months.

Have you tried zsh with histdb? It's been an absolute gamechanger. Having a complete, precise, and effectively infinite history is like a second brain.

I know not everyone is on the zsh train, but it might be able to be ported to bash (it's just pre-hooks and some sqlite)

https://github.com/larkery/zsh-histdb

A quick Google turns up this [1]. Haven't verified it works though.

1. https://github.com/thenewwazoo/bash-history-sqlite

Oh! I actually used this before switching to histdb. IIRC it works-ish but there was less polish than histdb.

Bash is the only shell I've ever used, but one day when time permits I'm looking forward to taking zsh for a test drive.

I've had the following in my ~/.bash_profile for quite some time. I leave it here in the hopes it help someone.

  ## History configuration, see HISTORY in bash(1)
  ## builtin fc, aka fix command, for history manipulation
  ## fc [-e ename] [-lnr] [first] [last]
  ##  -e or invoke editor ename; defaults to $FCEDIT
  ##  -l or list commands
  ##  -n or suppress entry numbers
  ##  -r or reverse command order
  ##  first, last selects a range of entries by numeric index
  ##
  ## fc -s [pat=rep] [cmd]
  ##  -s or substitute all occurences of pat with rep
  #
  #  - h() is short for history
  #  - r() is short for replay
  #  - always append to the history, don't overwrite
  #  - save multi-line commands in a single entry
  #  - insist on vim everywhere
  #  - don't record commands with a leading space or duplicates
  #  - constrain the size of the history file
  #  - ignore common things
  #  - constrain the number of history entries
  #  - set up nicer timestamps
  alias h="history"
  alias r="fc -s"
  shopt -s histappend
  shopt -s cmdhist
  export FCEDIT=$EDITOR
  export HISTCONTROL=ignoreboth
  export HISTFILE=$HOME/.bash_history
  export HISTFILESIZE=1048576
  export HISTIGNORE='ls:ls -l:ls -latr:ps -ef:fc:h:history:clear:exit'
  export HISTSIZE=8192
  export HISTTIMEFORMAT='[%F %T]  '

Thanks, @tiny_epoch -- that was helpful. :)