March 2022

I’m a long time bash user and have found that I really want more information in my bash history file … more than just the typical command number and command line. So, to my .bashrc I’ve added a time stamp, process id, and tty to the history output by setting HISTTIMEFORMAT like so

export HISTTIMEFORMAT="%F %T %Z %z $$ $TTY "

which produces something like

957 2022-03-02 10:37:05 PST -0800 684 /dev/pts/0 history | tail

As you can see, this adds, after the command number, the date as YYYY-MM-DD, the time with timezone and GMT offset, the process id and the tty on which it was entered. I also like to keep track of the commands that are entered when I’m in a certain directory (useful for git and, well, all sorts of things) so I add

export PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND ; }"'echo $TTY $$ $USER \
$PWD "$(history 1)" >> ~/.history/$(basename $PWD)'

This appends a history line to a directory in ~/.history which corresponds to the last component of the directory in which the command was entered. So, if my current working directory is ~/dev/git, commands are also appended to ~/.history/git along with the tty on which they were entered, the current process id, the current user and the full working directory which gives me something like

/dev/pts/1 1806 user /home/user/git 951 2022-03-02 10:47:00 PST -0800 1806 /dev/pts/1 ls -l ~/.history

Note, I don’t change HISTFILE so everything is still in one history file. And I use an alias to show history for the current directory

alias cathist='cat ~/.history/$(basename $PWD)'

And, while I’m at it, I enable host name completion with shopt -s hostcomplete and also ask bash to try to save a multiline command in one history entry with shopt -s cmdhist. And if I have lots of space, I allow my history file to grow as large as needed by setting (or unsetting) HISTFILESIZE and HISTSIZE. So I end up with the following lines added to my .bashrc

export HISTSIZE=
export HISTFILESIZE=
shopt -s histappend
shopt -s cmdhist
shopt -s hostcomplete

export HISTTIMEFORMAT="%F %T %Z %z $$ $TTY "
TTY=$(tty)

export PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND ; }"'echo $TTY $$ $USER \
$PWD "$(history 1)" >> ~/.history/$(basename $PWD)'

alias cathist='cat ~/.history/$(basename $PWD)

I picked this up from various sources and modified it to fit my needs. Feel free to use or hack as you see fit.